JEE Advanced (Fill in the Blanks): The p-Block Elements | Chapter-wise Tests for JEE Main & Advanced PDF Download

Fill in the Blanks

Q.1. The lowest possible oxidation state of nitrogen is        (1980)

Ans. –3

Solution. –3;

Q.2. Iodine reacts with hot NaOH solution. The products are NaI and .......      (1980)

Ans. NaIO₃

Solution. NaIO₃

Q.3. ................. is a weak acid. (HF, HCl, HI)                 (1981 - 1 Mark)

Ans. HF

Solution. HF; HF is the weakest of the three, because the ionisation (i.e. acidic character) of HX is a multistep process and when its DH, heat of ionisation, is calculated it comes out to be the minimum. This is due to the strong H – F bond, large heat of hydration (because of H-bonding) and low value of electron affinity of F-atom.

Q.4. The increase in the solubility of iodine in an aqueous solution of potassium iodide is due to the formation of ............. .              (1982 - 1 Mark)

Ans. KI₃

Solution. KI₃; complexes are more soluble in water as compared to normal salts. [KI+I₂ → KI₃]

Q.5. Hydrogen gas is liberated by the action of aluminium with concentrated solution of .............. .               (1987 - 1 Mark)

Ans. sodium hydroxide

Solution. sodium hydroxide;

Al + 2NaOH + 2H₂O → 2NaAlO₂ +3H₂

Q.6. .............. phosphorus is reactive because of its highly strained tetrahedral structure.      (1987 - 1 Mark)

Ans. white/ yellow

Solution. white/ yellow; NOTE : In white phosphorus, each phosphorus atom is linked to the other three atoms by covelent bonds. PPP bond angle is 60°, due to which the molecule remains under strain and hence is active in nature.

Q.7. ............... acid gives hypo ............... ion.         (1988 - 1 Mark) 

(hydrobromic, hypobromous, perbromic, bromide, bromite, perbromate)

Ans. hypobromous, bromide

Solution. Hypobromous; bromite. 

Q.8. Sulphur acts as ............... agent in vulcanization of rubber.             (1989 - 1 Mark)

Ans. cross -linking

Solution. cross-linking;

Q.9. The basicity of phosphorous acid (H₃PO₃) is ............... .                  (1990 - 1 Mark)

Ans. two

Solution.   [It contains two replaceable hydrogens.]

Q.10. The hydrolysis of alkyl substituted chlorosilan es gives .............. .

Ans. silicones

Solution. Silicones;

Q.11. In P₄O₁₀, the number of oxygen atoms bonded to each phosphorus atom is ............... .           (1992 - 1 Mark)

Ans. 4

Solution. four. 

In each P atom is linked to 4 oxygen atoms

Q.12. The lead chamber process involves oxidation of SO₂ by atomic oxygen under the influence of ............... as catalyst.               (1992 - 1 Mark)

Ans. Nitric oxide

Solution. Nitric oxide. [NO]

The mixture containing SO₂, air and nitric oxide, when treated with steam, sulphuric acid is formed.

Q.13. The hydrolysis of trialkylchlorosilane R₃SiCl, yields ...........                      (1994 - 1 Mark)

Ans. trialkylchlorosilanol

Solution. Trialkylchlorosilanol; The hydrolysis of R₃SiCl, yields R₃Si(OH) which condenses to give R₃ Si – O – SiR₃

Q.14. One recently discovered allotrope of carbon (e.g., C₆₀) is commonly known as...........                 (1994 - 1 Mark)
 Ans. fullerene

Solution. Fullerene

Q.15. Solubility of iodine in water is greatly increased by the addition of iodide ions because of the formation of ........            (1994 - 1 Mark)

Ans.  I^–₃ complex ion

Solution. I^–₃ complex ion   I₂ + I^– ——→ I₃^-

Q.16. A liquid which is permanently supercooled is frequently called a ........... .           (1997 - 1 Mark)

Ans. glass

Solution. glass

Q.17. Compounds that formally contain Pb⁴⁺ are easily reduced to Pb²⁺. The stability of the lower oxidation state is due to ........... . (1997 - 1 Mark)

Ans. inert-pair effect

Solution. inert-pair effect ; When ns² electrons of outermost shell do not participate in bonding it is called inert pair and the effect is called inert pair effect.