Q: Do you expect different products in solution when aluminium(III) chloride and potassium chloride treated separately with (i) normal water (ii) acidified the water, and (iii) alkaline water? Write equations wherever necessary.

\$KCl\$ is a salt of strong acid \$HCl\$ and strong base \$KOH\$. Such salts are neutral in nature and do not undergo hydrolysis. In neutral water, acidic water and alkaline water, \$KCl\$ dissociates as\$\displaystyle KCl \xrightarrow {Water} K^+ + Cl^-\$\$\displaystyle AlCl_3 \$ is a salt of strong acid \$HCl\$ and weak base \$\displaystyle Al(OH)_3 \$.In normal water, it is hydrolyzed.\$\displaystyle AlCl_3+3H_2O \rightarrow Al(OH)_3 + 3H^++3Cl^- \$ In acidic water, \$\displaystyle H^+ \$ ions react with \$\displaystyle Al(OH)_3 \$ forming water and \$\displaystyle Al^{3+} \$ ions. Hence it exists as \$\displaystyle Al^{3+}+Cl^- \$\$\displaystyle AlCl_3 \xrightarrow [water]{acidified} Al^{+}+3Cl^- \$In alkaline water, the reaction is \$\displaystyle Al(OH)_3 + OH^- \rightarrow [Al(OH)_4]^- \$

Q: Complete the following reactions:(i) \$H_2\, (g)\, +\, M_{m}O_o\, (s)\, \overset{\Delta}{\rightarrow}\$(ii) \$CO\, (g)\, +\, H_2\, (g)\, \xrightarrow[catalyst]{\Delta }\$(iii) \$C_3H_8\, (g)\, +\, 3H_2O\, (g)\, \xrightarrow[catalyst]{\Delta }\$(iv) \$C_3H_8\, (g)\, +\, 3H_2O\, (g)\, \xrightarrow[catalyst]{\Delta }\$

The complete reaction is as follows:\$\displaystyle oH_2\, (g)\, +\, M_{m}O_o\, (s)\, \overset{\Delta}{\rightarrow} mM(s) + oH_2O(l) \$\$\displaystyle CO\, (g)\, +\, H_2\, (g)\, \xrightarrow[\text { catalyst}]{\Delta } \underset {\text { methanol}}{CH_3OH(l)} \$\$\displaystyle C_3H_8\, (g)\, +\, 3H_2O\, (g)\, \xrightarrow[\text { catalyst}]{\Delta } 3CO(g)+7H_2(g) \$\$\displaystyle Zn\, (s)\, +\, NaOH\, (aq)\, \xrightarrow[]{\text { heat}} \underset {\text { Sodium zincate}}{Na_2ZnO_2(aq)} + H_2(g) \$

Q: Saline hydrides are known to react with water violently producing fire. Can \$CO_2\$, a well known fire extinguisher, be used in this case? Explain.

Saline hydrides such as \$\displaystyle NaH,CaH_2 \$ violently react with water and form metal hydroxide and hydrogen gas.\$\displaystyle NaH(s) + H_2O(l) \rightarrow NaOH(aq) + H_2(g)\$\$\displaystyle CaH_2(s) + 2H_2O(l) \rightarrow Ca(OH)_2(aq) +2H_2(g) \$ During these reactions, large amount of energy is released so that hydrogen catches fire. \$\displaystyle CO_2\$ cannot extinguish this fire as it is reduced by hot metal hydride. \$\displaystyle NaH+CO_2 \rightarrow HCOONa\$To extinguish this fire, sand (a highly stable solid) can be used.

Q: Consider the reaction of water with \$F_2\$ and suggest in terms of oxidation and reduction which species are oxidised/reduced.

The balanced chemical equations are given below.\$\displaystyle 2F_2 + 2H_2O \rightarrow O_2 + 4H^+ + 4F^- \$\$\displaystyle 3F_2 + 3H_2O \rightarrow O_3 + 6H^+ + 6F^- \$Thus, water is a reductant and itself is oxidized to oxygen or ozone. Fluorine is an oxidant and itself is reduced to fluoride ion.

Q: Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful?

Water contains several important nutrients required by humans, plants and animals for survival. In demineralized water, all soluble minerals are removed. Hence, this water is not suitable for drinking. In distilled water, all the minerals are present but the microorganisms are killed. Hence, distilled water is suitable for drinking.

Q: Complete the following chemical reaction and classify into (a) hydrolysis, (b) redox and (c) hydration reaction. \$AlCl_3\, (g)\, +\, H_2O\, (l)\, \rightarrow\$

The complete reaction is given below-\$\displaystyle AlCl_3(g) +3H_2O(l) \rightarrow Al(OH)_3(s) + 3HCl(aq)\$This is an example of hydrolysis reaction.

Q: What do you understand by the term 'auto-protolysis' of water? What is its significance?

The reaction between two water molecules to produce hydronium ion and hydroxide ion is known as autoprotolysis of water. This is self ionization of water.\$\displaystyle 2H_2O \rightarrow H_3O^++OH^- \$ This reaction indicates the amphoteric nature of water. It can act as an acid as well as a base. One water molecule donates electron whereas other water molecule accepts electron.

Question 1

What properties of water make it useful as a solvent? What type of compound can it (i) dissolve and (ii) hydrolyse?

Accepted Answer

Water is good solvent due to high dielectric constant, high liquid range and ability to dissolve most of compounds. Water is good solvent for ionic compounds but poor solvent for covalent compounds. It can hydrolyze ionic compounds.

Question 2

How does $H_2O_2$ behave as a bleaching agent.

Accepted Answer

In acidic and basic media, hydrogen peroxide is strong oxidizing agent. $\displaystyle 2H_2O_2 \rightarrow 2H_2O + O_2 $It breaks chemical bonds (oxidative degradation) of the chromophores (that produce colour) in the cloth. Due to this, visible light is not absorbed and the cloth gets whitened.

Question 3

Do you expect different products in solution when aluminium(III) chloride and potassium chloride treated separately with (i) normal water (ii) acidified the water, and (iii) alkaline water? Write equations wherever necessary.

Accepted Answer

$KCl$ is a salt of strong acid $HCl$ and strong base $KOH$. Such salts are &#10;neutral in nature and do not undergo hydrolysis. In neutral water, &#10;acidic water and alkaline water, $KCl$ dissociates as$\displaystyle KCl \xrightarrow {Water} K^+ + Cl^-$$\displaystyle AlCl_3 $ is a salt of strong acid $HCl$ and weak base $\displaystyle Al(OH)_3 $.In normal water, it is hydrolyzed.$\displaystyle AlCl_3+3H_2O \rightarrow Al(OH)_3 + 3H^++3Cl^- $ In&#10; acidic water, $\displaystyle H^+ $ ions react with $\displaystyle &#10;Al(OH)_3 $ forming water and $\displaystyle Al^{3+} $ ions.  Hence it&#10; exists as $\displaystyle Al^{3+}+Cl^- $$\displaystyle AlCl_3 \xrightarrow [water]{acidified} Al^{+}+3Cl^- $In alkaline water, the reaction is $\displaystyle Al(OH)_3 + OH^- \rightarrow [Al(OH)_4]^- $

Question 4

Complete the following reactions:(i) $H_2\, (g)\, +\, M_{m}O_o\, (s)\, \overset{\Delta}{\rightarrow}$(ii) $CO\, (g)\, +\, H_2\, (g)\, \xrightarrow[catalyst]{\Delta }$(iii) $C_3H_8\, (g)\, +\, 3H_2O\, (g)\, \xrightarrow[catalyst]{\Delta }$(iv) $C_3H_8\, (g)\, +\, 3H_2O\, (g)\, \xrightarrow[catalyst]{\Delta }$

Accepted Answer

The complete reaction is as follows:$\displaystyle oH_2\, (g)\, +\, M_{m}O_o\, (s)\, \overset{\Delta}{\rightarrow} mM(s) + oH_2O(l) $$\displaystyle CO\, (g)\, +\, H_2\, (g)\, \xrightarrow[\text { catalyst}]{\Delta } \underset {\text { methanol}}{CH_3OH(l)} $$\displaystyle C_3H_8\, (g)\, +\, 3H_2O\, (g)\, \xrightarrow[\text { catalyst}]{\Delta } 3CO(g)+7H_2(g) $$\displaystyle Zn\, (s)\, +\, NaOH\, (aq)\, \xrightarrow[]{\text { heat}} \underset {\text { Sodium zincate}}{Na_2ZnO_2(aq)} + H_2(g) $

Question 5

Saline hydrides are known to react with water violently producing fire. Can $CO_2$, a well known fire extinguisher, be used in this case? Explain.

Accepted Answer

Saline hydrides such as $\displaystyle NaH,CaH_2 $ violently react with water and form metal hydroxide and hydrogen gas.$\displaystyle  NaH(s) + H_2O(l) \rightarrow NaOH(aq) + H_2(g)$$\displaystyle CaH_2(s) + 2H_2O(l) \rightarrow Ca(OH)_2(aq) +2H_2(g) $ During these reactions, large amount of energy is released so that hydrogen catches fire. $\displaystyle  CO_2$ cannot extinguish this fire as it is reduced by hot metal hydride. $\displaystyle  NaH+CO_2 \rightarrow HCOONa$To extinguish this fire, sand (a highly stable solid) can be used.

Question 6

Consider the reaction of water with $F_2$ and suggest in terms of oxidation and reduction which species are oxidised/reduced.

Accepted Answer

The balanced chemical equations are given below.$\displaystyle 2F_2 + 2H_2O \rightarrow O_2 + 4H^+ + 4F^- $$\displaystyle 3F_2 + 3H_2O \rightarrow O_3 + 6H^+ + 6F^- $Thus, water is a reductant and itself is oxidized to oxygen or ozone. Fluorine is an oxidant and itself is reduced to fluoride ion.

Question 7

Arrange the following $LiH, NaH$ and $CsH$ in order of increasing ionic character.

Accepted Answer

The ionic character of bond depends on electronegativity difference between two atoms. When the electronegativity difference is larger, the ionic character is smaller. On moving down the group of alkali metals, the electronegativity decreases from Li to Cs. Hence the ionic character increases in the order $\displaystyle LiH < NaH < CsH $.

Question 8

Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful?

Accepted Answer

Water contains several important nutrients required by humans, plants and animals for survival. In demineralized water, all soluble minerals are removed. Hence, this water is not suitable for drinking. In distilled water, all the minerals are present but the microorganisms are killed. Hence, distilled water is suitable for drinking.

Question 9

Complete the following chemical reaction and classify into (a) hydrolysis, (b) redox and (c) hydration reaction. $AlCl_3\, (g)\, +\, H_2O\, (l)\, \rightarrow$

Accepted Answer

The complete reaction is given below-$\displaystyle  AlCl_3(g) +3H_2O(l) \rightarrow Al(OH)_3(s) + 3HCl(aq)$This is an example of hydrolysis reaction.

Question 10

What do you understand by the term 'auto-protolysis' of water? What is its significance?

Accepted Answer

The reaction between two water molecules to produce hydronium ion and hydroxide ion is known as autoprotolysis of water. This is self ionization of water.$\displaystyle 2H_2O \rightarrow H_3O^++OH^- $ This reaction indicates the amphoteric nature of water. It can act as an acid as well as a base. One water molecule donates electron whereas other water molecule accepts electron.

Hydrogen

NCERT

Exercise

What properties of water make it useful as a solvent? What type of compound can it (i) dissolve and (ii) hydrolyse?

How does $H_{2} O_{2}$ behave as a bleaching agent.

Do you expect different products in solution when aluminium(III) chloride and potassium chloride treated separately with (i) normal water (ii) acidified the water, and (iii) alkaline water? Write equations wherever necessary.

Complete the following reactions:

(i) $H_{2} (g) + M_{m} O_{o} (s) \to Δ$
(ii) $C O (g) + H_{2} (g) Δ c a t a l y s t$
(iii) $C_{3} H_{8} (g) + 3 H_{2} O (g) Δ c a t a l y s t$
(iv) $C_{3} H_{8} (g) + 3 H_{2} O (g) Δ c a t a l y s t$

Saline hydrides are known to react with water violently producing fire. Can $C O_{2}$ , a well known fire extinguisher, be used in this case? Explain.

Consider the reaction of water with $F_{2}$ and suggest in terms of oxidation and reduction which species are oxidised/reduced.

Arrange the following $L i H, N a H$ and $C s H$ in order of increasing ionic character.

Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful?

Complete the following chemical reaction and classify into (a) hydrolysis, (b) redox and (c) hydration reaction.
$A l C l_{3} (g) + H_{2} O (l) \to$

What do you understand by the term 'auto-protolysis' of water? What is its significance?

Hydrogen

NCERT

Exercise

What properties of water make it useful as a solvent? What type of compound can it (i) dissolve and (ii) hydrolyse?

How does H2​O2​ behave as a bleaching agent.

Do you expect different products in solution when aluminium(III) chloride and potassium chloride treated separately with (i) normal water (ii) acidified the water, and (iii) alkaline water? Write equations wherever necessary.

Complete the following reactions: (i) H2​(g)+Mm​Oo​(s)→Δ (ii) CO(g)+H2​(g)Δcatalyst​ (iii) C3​H8​(g)+3H2​O(g)Δcatalyst​ (iv) C3​H8​(g)+3H2​O(g)Δcatalyst​

Saline hydrides are known to react with water violently producing fire. Can CO2​, a well known fire extinguisher, be used in this case? Explain.

Consider the reaction of water with F2​ and suggest in terms of oxidation and reduction which species are oxidised/reduced.

Arrange the following LiH,NaH and CsH in order of increasing ionic character.

Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful?

Complete the following chemical reaction and classify into (a) hydrolysis, (b) redox and (c) hydration reaction. AlCl3​(g)+H2​O(l)→

What do you understand by the term 'auto-protolysis' of water? What is its significance?

How does $H_{2} O_{2}$ behave as a bleaching agent.

Complete the following reactions:

(i) $H_{2} (g) + M_{m} O_{o} (s) \to Δ$
(ii) $C O (g) + H_{2} (g) Δ c a t a l y s t$
(iii) $C_{3} H_{8} (g) + 3 H_{2} O (g) Δ c a t a l y s t$
(iv) $C_{3} H_{8} (g) + 3 H_{2} O (g) Δ c a t a l y s t$

Saline hydrides are known to react with water violently producing fire. Can $C O_{2}$ , a well known fire extinguisher, be used in this case? Explain.

Consider the reaction of water with $F_{2}$ and suggest in terms of oxidation and reduction which species are oxidised/reduced.

Arrange the following $L i H, N a H$ and $C s H$ in order of increasing ionic character.

Complete the following chemical reaction and classify into (a) hydrolysis, (b) redox and (c) hydration reaction.
$A l C l_{3} (g) + H_{2} O (l) \to$