Question 1

Which of the following is incorrect statement ?

Accepted Answer

PbF_4  and  SnF_4  are ionic in nature.Hence option A is the correct answer.

Question 2

Which of the following species is not stable?

Accepted Answer

Due to presence of d-orbital in  Si,\ Ge  and  Sn  they form species like  [SiF_6]^{2-},\ [GeCl_6]^{2-}, \ [Sn(OH)_6]^{2-}  but  SiCl^{2-}_6  does not exist because six large chloride ions cannot be accommodated around  Si^{4+}  due to limitation of its size.

Question 3

Identify the correct statements from the following :
a)

C O_{2} (g)

is used as refrigerant for ice-cream and frozen food.
b) The structure of

C_{60}

contains twelve six-carbon rings and twenty-five carbon rings.
c)

Z S M - 5

, a type of zeolite, is used to convert alcohol into gasoline.
d)

C O

is a colorless and odourless gas

Accepted Answer

a)  CO_2  in solid state used as refrigerant for ice-cream and frozen food because of its sublimation properties. Sublimation is a process in which a solid directly goes into gaseous state without going into liquid state.b) The structure of  C_{60}  contains twelve five-carbon rings and twenty six-carbon rings. Hence the given statement was wrong.c)  ZSM-5 , a type of zeolite, is used to convert alcohol into gasoline. The statement is correct.d)  CO  is a colorless and odourless gas. True.Statements (c) and (d) are correct. Option C is correct.

Question 4

Which of the following is not correct about carbon monoxide?

Accepted Answer

Carboxyhaemoglobin (symbol COHb or HbCO) is a stable complex of carbon monoxide and haemoglobin (Hb) that forms in red blood cells upon contact with carbon monoxide (CO). The CO-hemoglobin complex is far more stable than  O_2 -hemoglobin (oxyhemoglobin)Hence statement B is incorrect.Option B is correct.

Question 5

What is the change in oxidation number of carbon in the following reaction? CH_4 (g) + 4Cl_2 (g)\longrightarrow CCl_4 (l) + 4HCl(g)

Accepted Answer

\overset {-4} CH_4 (g) + 4Cl_2 (g)\longrightarrow \overset {+4} CCl_4 (l) + 4HCl(g) The oxidation state of  H  and  Cl  are +1 and -1 respectively. Therefore the oxidation state of C in methane is  -4  and that in carbon tetrachloride is  +4 .

Some P-Block Elements