21. An aqueous solution of a substance gives a white precipitate on treatment with dilute hydrochloric acid, which dissolves on heating. When hydrogen sulfide is passed through the hot acidic solution, a black precipitate is obtained. The substance is a
A
$$Hg_2^{2 + }\,{\text{salt}}$$
B
$$C{u^{2 + }}{\text{salt}}$$
C
$$A{g^ + }\,{\text{salt}}$$
D
$$P{b^{2 + }}\,{\text{salt}}$$
Answer :
$$P{b^{2 + }}\,{\text{salt}}$$
22. Identify the correct order of solubility of $$N{a_2}S,\,CuS\,{\text{and}}\,ZnS$$ in aqueous medium
A
$$CuS > ZnS > N{a_2}S$$
B
$$ZnS > N{a_2}S > CuS$$
C
$$N{a_2}S > CuS > ZnS$$
D
$$N{a_2}S > ZnS > CuS$$
Answer :
$$N{a_2}S > ZnS > CuS$$
23. The salt used for performing 'bead' test in qualitative inorganic analysis is
A
$${K_2}S{O_4}.A{l_2}{\left( {S{O_4}} \right)_3}.24{H_2}O$$
B
$$FeS{O_4}.{\left( {N{H_4}} \right)_2}S{O_4}4{H_2}O$$
C
$$Na\left( {N{H_4}} \right)HP{O_4}.4{H_2}O$$
D
$$CaS{O_4}.2{H_2}O$$
Answer :
$$Na\left( {N{H_4}} \right)HP{O_4}.4{H_2}O$$
24. A pink coloured salt turns blue on heating. The presence of which cation is most likely ?
A
$$C{o^{2 + }}$$
B
$$C{u^{2 + }}$$
C
$$Z{n^{2 + }}$$
D
$$F{e^{2 + }}$$
Answer :
$$C{o^{2 + }}$$
25. A metal chloride dissolves appreciably in cold water. When placed on a platinum wire in Bunsen flame no distinctive colour is noticed, the cation would be
A
$$M{g^{2 + }}$$
B
$$B{a^{2 + }}$$
C
$$P{b^{2 + }}$$
D
$$C{a^{2 + }}$$
Answer :
$$M{g^{2 + }}$$
26. The cation that will not be precipitated by $${H_2}S$$ in the presence of dil. $$HCl$$ is :
A
$$P{b^{2 + }}$$
B
$$C{u^{2 + }}$$
C
$$C{o^{2 + }}$$
D
$$A{s^{3 + }}$$
Answer :
$$C{o^{2 + }}$$
27. A solution of a metal ion when treated with $$KI$$ gives a red precipitate which dissolves in excess $$KI$$ to give a colourless solution. Moreover, the solution of metal ion on treatment with a solution of cobalt (II) thiocyanate gives rise to a deep blue crystalline precipitate. The metal ion is
A
$$P{b^{2 + }}$$
B
$$H{g^{2 + }}$$
C
$$C{u^{2 + }}$$
D
$$C{o^{2 + }}$$
Answer :
$$H{g^{2 + }}$$
28.
The correct match between Item-I and Item-II is:
A
$$A \to R;B \to P;C \to S;D \to Q$$
B
$$A \to Q;B \to S;C \to P;D \to R$$
C
$$A \to R;B \to S;C \to P;D \to Q$$
D
$$A \to Q;B \to P;C \to S;D \to R$$
Answer :
$$A \to R;B \to S;C \to P;D \to Q$$
.PNG "Qualitative Analysis mcq solution image")
.PNG "Qualitative Analysis mcq solution image")
.PNG "Qualitative Analysis mcq solution image")
29. Passing $${H_2}S$$ gas into a mixture of $$M{n^{2 + }},N{i^{2 + }},C{u^{2 + }}\,{\text{and}}\,H{g^{2 + }}$$ ions in an acidified aqueous solution precipitates
A
$$CuS\,{\text{and}}\,HgS$$
B
$$MnS\,{\text{and}}\,CuS$$
C
$$MnS\,{\text{and}}\,NiS$$
D
$$NiS\,{\text{and}}\,HgS$$
Answer :
$$CuS\,{\text{and}}\,HgS$$
30. Which one of the following statements is correct?
A
From a mixed precipitate of $$AgCl\,{\text{and}}\,Agl,$$ ammonia solution dissolves only $$AgCl$$
B
Ferric ions give a deep green precipitate on adding potassium ferrocyanide solution
C
On boiling a solution having $${K^ + },C{a^{2 + }}\,{\text{and}}\,HCO_3^ - $$ ions we get a precipitate of $${K_2}Ca{\left( {C{O_3}} \right)_2}$$
D
Manganese salts give a violet borax bead test in the reducing flame
Answer :
From a mixed precipitate of $$AgCl\,{\text{and}}\,Agl,$$ ammonia solution dissolves only $$AgCl$$