WB JEE 2022 | Some s Block Elements Question 3 | Chemistry

1

WB JEE 2022

MCQ (Single Correct Answer)

+1

-0.25

To a solution of colourless sodium salt, a solution of lead nitrate was added to have a white precipitate which dissolves in warm water and reprecipitates on cooling. Which of the following acid radical is present in the salt?

A

Cl^$$-$$

B

SO$$_4^{2 - }$$

C

S^2$$-$$

D

NO$$_3^{ - }$$

2

WB JEE 2021

MCQ (Single Correct Answer)

+1

-0.25

Indicate the products (X) and (Y) in the following reactions

Na₂S + nS(n = 1 $$-$$ 8) $$\to$$ (X)

Na₂SO₃ + S $$\to$$ (Y)

A

(X)	(Y)
$$N{a_2}{S_2}{O_3}$$	$$N{a_2}{S_2}$$

B

(X)	(Y)
$$N{a_2}{S_{(n + 1)}}$$	$$N{a_2}{S_2}{O_3}$$

C

(X)	(Y)
$$N{a_2}{S_n}$$	$$N{a_2}{S_2}{O_3}$$

D

(X)	(Y)
$$N{a_2}{S_5}$$	$$N{a_2}{S_2}{O_4}$$

3

WB JEE 2021

MCQ (Single Correct Answer)

+1

-0.25

The white precipitate (Y), obtained on passing colorless and odourless gas (X) through an ammoniacal solution of NaCl, losses about 37% of its weight on heating and a white residue (Z) of basic nature is left. Identify (X), (Y) and (Z) from following sets.

A

(X)	(Y)	(Z)
$${N_2}$$	$${(N{H_4})_2}C{O_3}$$	$$N{H_4}Cl$$

B

(X)	(Y)	(Z)
$${O_2}$$	$$NaN{H_4}C{O_3}$$	$$NaHC{O_3}$$

C

(X)	(Y)	(Z)
$$C{O_2}$$	$$N{H_4}HC{O_3}$$	$${(N{H_4})_2}C{O_3}$$

D

(X)	(Y)	(Z)
$$C{O_2}$$	$$NaHC{O_3}$$	$$N{a_2}C{O_3}$$

4

WB JEE 2020

MCQ (Single Correct Answer)

+1

-0.25

In the extraction of Ca by electro reduction of molten CaCl₂ some CaF₂ is added to the electrolyte for the following reason :

A

To keep the electrolyte in liquid state at temperature lower than the m.p. of CaCl₂

B

To effect precipitation of Ca

C

To effect the electrolysis at lower voltage

D

To increase the current efficiency