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NCERT Solutions for Class 11 Chemistry I Chapter 3 to 6

Exercise

21 Qs

Related questions

Choose the correct answer. 
A thermodynamic state function is a quantity : 

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For the process to occur under adiabatic conditions, the correct condition is :

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The enthalpies of all elements in their standard states are : 

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of combustion of methane is . The value of  is:

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The enthalpy of combustion of methane graphite and dihydrogen at are kJ  and kJ  respectively. Enthalpy of formation of  will be:

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A reaction A+B C+D is found to have a positive entropy change. The reaction will be :

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In a process, 701 J of heat is absorbed by a system and 394 J of work is done by the system. What is the change in internal energy for the process?

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The reaction of cyanamide with dioxygen was carried out in a bomb calorimeter and  was found to be at 298 K. 


Calculate enthalpy change for the reaction at 298 K?

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Calculate the enthalpy change on freezing of  of water at  to ice at 
   at




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Enthalpy of combustion of carbon to is -393.5 kJ . Calculate the heat released upon formation of 35.2g of  from carbon and dioxygen gas.

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Enthalpies of formation of CO(g),   and  are and respectively. Find the value of  for the reaction :


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What is the standard enthalpy of formation of gas?

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From the following data of heats of combustion, find the heat of formation of



 

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Calculate the enthalpy change for the process 


and calculate bond enthalpy of C-Cl in

kJ mol

kJ mol

kJ mol.  

where   is enthalpy of atomisation 

kJ mol

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For an isolated system  U=0 what will be S?

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For the reaction at 298 K, 2A+B

H = 400 KJ  and  S = 0.02 KJ  

At what temperature will the reaction become spontaneous considering  H and  S  to be constant over the temperature range?

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For the reaction,
what are the signs of H and S ?

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For the reaction,
2 A(g)+ B(g) 2D(g), and

Calculate  for the reaction and predict whether the reaction may occur spontaneously.

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The equilibrium constant for a reaction is 10. what will be value of  ? R =8.314 , T=300 K

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Comment on the thermodynamic stability of NO(g) given 


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Calculate the entropy change in surrounding when 1.00 mol of   is formed under standard condition .

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Exercise

22 Qs

Related questions

What will be the minimum pressure required to compress 500 dm of air at 1 bar to 200 dm at 30 C?

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A vessel of  capacity contain amount of gas at  and  bar pressure The gas is transferred to another vessel of volume  at . What would be its pressure?

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Using the equation of state , show that, at a given temperature the density of a gas is proportional to its gas pressure .

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At  the density of certain oxide of a gas at bar is same as that of dinitrogen at bar. What is the molecular mass of the oxide?

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Pressure of 1 g of an ideal gas A at 27  is found to be 2 bar. When 2 g of another ideal gas B is introduced in the same flask at same temperature the pressure becomes 3 bar. Find a relationship between their molecular masses?

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The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at and one bar will be released when  of aluminum reacts?

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What will be the pressure exerted by a mixture of of methane and of contained in a flask at .

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What will be the pressure of the gaseous mixture when 0.5 L of H at 0.8 bar and 2.0 L of dioxygen at 0.7 bar are introduced in a 1L vessel at 27 ?

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Density of a gas is found to be 5.46 dm at 27  at 2 bar pressure. What will be its density at STP? 

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34.05 mL of phosphorus vapour weighs 0.0625 g at 546  and 0.1 bar pressure. What is the molar mass of phosphorus?

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A student forgot to add the reaction mixture to the round bottomed flask at  but instead he/she placed the flask on the flame. After a lapse of time, he realized his mistake, and using a pyrometer he found the temperature of the flask was . What fraction of air would have been expelled out?

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Calculate the temperature of 4.0 mol of a gas occupying 5 dm at 3.32 bar.
(R = 0.083 bar dm K mol )

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Calculate the total number of electrons present in 1.4 g of dinitrogen gas.

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How much time would it take to distribute one Avogadro number of wheat grains, if grains are distributed each second?

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Calculate the total pressure in a mixture of 8 g of dioxygen and 4 g of dihydrogen confined in a vessel of 1 dm at 27 . (R = 0.083 bar dm K mol)

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Payload is defined as the difference between the mass of displaced air and the mass of the balloon. Calculate the payload, when a balloon of radius 10 m of mass 100 kg is filled with helium at 1.66 bar at 27 . (Density of air = 1.2 kg m and R = 0.083 bar dm K mol)

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Calculate the volume occupied by 8.8 g of CO at 31.1 and 1 bar pressure. (R = 0.083 bar L K mol)

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g of gas at  occupied the same volume as 0.184 g of dihydrogen at  at the same pressure. What is the molar mass of the gas?

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A mixture of dihydrogen and dioxygen at one bar pressure contains 20% by weight of dihydrogen. Calculate the partial pressure of dihydrogen.

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In terms of Charles' law, explain why - 273  is the lowest possible temperature.

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Critical temperature for carbon dioxide and methane are  and  respectively. Which of these has stronger intermolecular forces and why?

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Explain the physical significance of Van der Waals parameters.

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Exercise

40 Qs

Related questions

Explain the formation of a chemical bond.

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Write Lewis dot symbols for atoms of the following elements :

 Mg, Na, B, O, N and Br.

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Write Lewis symbols for the following atoms and ions :

(i) and

(ii) and 
 
(iii) and 

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Draw the Lewis structures for the following molecules and ions :

and

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Define octet rule and write its significance and limitations.

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Write the favourable factors for the formation of ionic bond :

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Determine the shape of the following molecules using the VSEPR model.



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Although geometries of  and molecules are distorted tetrahedral, bond angle in water is less than that of ammonia. Discuss :

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How is the bond strength related to the bond order?

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Define bond length in a molecule.

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Explain the important aspects of resonance with reference to the  ion.

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can be represented by structures 1 and 2 shown above. Can these two structures be taken as the canonical forms of the resonance hybrid representing  ? If not, give reasons for the same.

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Write the resonance structures for  and .

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Use Lewis symbols to show electron transfer between the following atoms to form cations and anions: (a) and (b) and (c) and .

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Although both  and  are triatomic molecules, the shape of   molecule is bent while that of  is linear. Explain this on the basis of dipole moment.

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Write the significance/application of dipole moment.

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Define electronegativity? How does it differ from electron gain enthalpy ?

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Explain the polar covalent bond with the help of suitable example.

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Arrange the below molecules in order of increasing ionic character. and 

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The skeletal structure of  as shown above is correct but some of the bonds are shown incorrectly. Write the correct Lewis structure for acetic acid.

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Apart from tetrahedral geometry, another possible geometry of could be square planar with the four H atoms at the corners of the square and the C atom at its centre. Why  is not square planar?

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Explain why  molecule has a zero dipole moment although the bonds are polar.

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Which out of  and  has higher dipole moment and why?

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What is meant by hybridisation of atomic orbitals? Describe the shapes of hybrid orbitals :

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Describe the change in hybridisation of the atom in the following reaction :


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Is there any change in the hybridisation of  and  atoms as a result of the following reaction?


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Draw diagrams showing the formation of a double bond and a triple bond between carbon atoms in  and  molecules. 

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What is the total number of sigma and pi bonds in the following molecules?
(a)  
(b) 

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Considering axis as the internuclear axis, the overlap of which of the following orbitals will not form a sigma bond and why? 
(a) and   
(b) and  
(c)  and  
(d) and

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Which hybrid orbitals are used by carbon atoms in the following molecules?
 

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What do you understand by bond pairs and lone pairs of electrons? Illustrate by giving one example of each type.

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Distinguish between a sigma and a pi bond.

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Explain the formation of  molecule on the basis of valence bond theory.

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Write the important conditions required for the linear combination of atomic orbitals to form molecular orbitals :

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Use molecular orbital theory to explain why molecule does not exist.

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Compare the relative stability of the following species and indicate their magnetic properties :

(superoxide) and (peroxide).

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Write the significance of a plus and a minus sign shown in representing the orbitals.

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Describe the hybridisation in case of . Why are the axial bonds longer as compared to equatorial bonds?

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Define  hydrogen bond. Is it weaker or stronger than the Van der Waals forces?

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What is meant by the term bond order ? Calculate the bond order of ,   and .

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Exercise

40 Qs

Related questions

What is the basis theme of organisation in the periodic table?

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Which important property did Mendeleev use to classify the element in his periodic table and did he stick to that?

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What is the basic difference between the Mendeleev's Periodic Law and the Modern Periodic Law?

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On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.

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In terms of period and group where would you locate the element with Z = 114?

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Write the atomic number of the element present in the third period and seventeenth group of the periodic table

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Which element do you think would have been named by (i) Lawrence Berkeley Laboratory and (ii) Seaborg's group?

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Why do elements in the same group have similar physical and chemical properties?

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What does atomic radius and ionic radius really mean to you?

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How do atomic radius vary in a period and in a group? How do you explain the variation?

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What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.
(i) F (ii) Ar (iii) Mg (iii) Rb

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Consider the following species :

N , O ,F, Na , Mgand Al

(a) What is common in them?

(b) Arrange them in the order of increasing ionic radii.

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Explain why cation are smaller and anions are larger in radii than their parent atoms?

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What is the significance of the terms 'isolated gaseous atom' and 'ground state' while defining the ionization enthalpy and electron gain enthalpy?

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Energy of an electron in the ground state of the hydrogen atom is . Calculate the ionization enthalpy of atomic hydrogen in terms of J mol.

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Among the second period elements the actual ionization enthalpies are in the order .
With the help of information given above, explain the followng:
(i) Be has higher  H than B.
(ii) O has lower  H than N and F.

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How would you explain the fact that the first ionization enthalpy of sodium is lower then that of magnesium but its second ionization enthalpy is higher than that of magnesium?

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What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group? 

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The first ionization enthalpy values ( in kJ mol ) of group 13 element are :

B           Al        Ga        In        Tl
801       577     579       558     589

How would you explain this deviation from the general trend?

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Which of the following pair of elements would have a more negative electron gain enthalpy?
(i) O or F   (ii) F or Cl

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Would you expect the second electron gain enthalpy of oxygen as positive, more negative or less negative than the first? Justify your answer.

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What is the basic difference between the terms electron gain enthalpy and electronegativity?

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How would you react on this statement?

Electronegativity of nitrogen (N) on Pauling scale is 3.0 in all the nitrogen compounds.

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Describe the theory associated with the radius of an atom as it :

(a) gains an electron
(b) loses an electron

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Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.

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What are the major differences between metals and non-metals?

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Use the periodic table to answer the following questions.
(a) Identify an element with five electrons in the outer subshell.
(b) Identify an element that would tend to lose two electrons.
(c) Identify and element that would tend to gain two electrons.
(d) Identify the group having metal non-metal liquid as well as gas at the room 
temperature.

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The increasing order of reactivity among group 1 element is , whereas that among group 17 element is . Explain?

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Write the general outer electronic configuration of and block elements.

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Assign the position of the element having outer electronic configuration,
(i) nsnp for n=3, 
(ii) (n-1)dns for  n=4, and 
(iii) (n-2) f(n-1)d ns for n=6 in the periodic table.

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The first  and the second   ionization enthalpies (in kJ mol) and the  electron gain enthalpy (in kJ mol) of a few elements are given below:
ElementsH
I5207300-60
II4193051-48
III16813374-328
IV10081846-295
V23725251+48
VI7381451-40
Which of the above elements is likely to be :
(a) the least reactive element,
(b) the most reactive metal,
(c) the most reactive non-metal,
(d) the least reactive non-metal,
(e) the metal which can form a stable binary halide of the formula MX (X=halogen) and
(f) the metal which can form a predominantly stable covalent halide of the formula MX (X=halogen)?

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Predict the formulae of the stable binary compounds that would be formed by the combination of the following pairs of elements.
(a) Lithium and oxygen   
(b) Magnesium and nitrogen
(c) Aluminium and iodine 
(d) Silicon and oxygen
(e) Phosphorus and fluorine 
(f) Element 71 and fluorine

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In the modern periodic table the period indicates the value of:

1. atomic number 
2. atomic mass
3. principal quantum number
4. azimuthal quantum number

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Which of the following statements related to the modern periodic table is incorrect?
(a) The p-block has 6 columns because a maximum of 6 electrons can occupy all
    the orbitals in a p-shell
(b) The d-block has 8 columns because a maximum of 8 electrons can occupy all the orbitals in a d-subshell
(c) Each block contains a number of columns equal to the number of  electrons that can occupy that subshell
(d) The block indicates value of azimuthal quantum number (I) for the last subshell that received electrons in building up the electronic configuration

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Anything that influences the valence electrons will affect the chemistry of the element. Nuclear mass effects chemistry of valence electrons.

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The size of isoelectronic species , and is affected by :

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Which one of the following statements is incorrect in relation to ionization enthalpy?
(a) Ionization enthalpy increases for each successive electron.
(b) The greatest increases in ionization enthalpy is experienced on removal of electron from core noble gas configuration.
(c) End of valence electrons is marked by a big jump in ionization enthalpy.
(d) Removal of electron from orbitals bearing lower n value is easier than from orbital having higher n value.

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Considering the element and , write the correct order of their metallic character.

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Considering the elements B, C, N, F and Si the correct order of their 
non-metallic character is:

(a)   (b)
(c)   (d)

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Considering the elements F, Cl, O and N the correct order of their chemical reactivity in terms of oxidizing property is:
(a) F > Cl > O > N     (b) F > O > Cl > N
(c) Cl > F > O > N     (d) O > F > N > Cl

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