List of top Chemistry Questions on Qualitative Analysis asked in JEE Main

A first row transition metal (M) does not liberate \( \mathrm{H_2} \) gas from dilute HCl.

1 mol of aqueous solution of \( \mathrm{MSO_4} \) is treated with excess aqueous KCN and then \( \mathrm{H_2S(g)} \) is passed through the solution.

The amount of \( \mathrm{MS} \) (metal sulphide) formed from the above reaction is ________ mol.

In the group analysis of cations, Ba$^{2+}$ & Ca$^{2+}$ are precipitated respectively as 
 

Statement-I : Test for nitrite; sulphanilic acid and 1-napthylamine are used.
Statement-II : Acidified nitrite is di-azotized with sulphanilic acid and coupled with 1-napthylamine.
Select the correct statement.
In general tests of Ba$^{2+}$ and Ca$^{2+}$ give the respective tests as:
When sodium fusion extract of an organic compound was treated with CHCl$_3$, then violet colour of halogen appears. If 0.15 gm of the organic compound gives 0.12 gm of the silver halide, then find the percentage of halide in the organic compound.
Given below are two statements:
Statement I: In Lassaigne's test, the covalent organic molecules are transformed into ionic compounds.
Statement II: The sodium fusion extract of an organic compound having N and S gives prussian blue colour with FeSO4 and Na4[Fe(CN)6].
In the light of the above statements, choose the correct answer from the options given below.

Among the following cations, the number of cations which will give characteristic precipitate in their identification tests with
\(K_4\)[Fe(CN)\(_6\)] is : \[ {Cu}^{2+}, \, {Fe}^{3+}, \, {Ba}^{2+}, \, {Ca}^{2+}, \, {NH}_4^+, \, {Mg}^{2+}, \, {Zn}^{2+} \]

Given below are two statements:
Statement-I: The gas liberated on warming a salt with dil H2SO4, turns a piece of paper dipped in lead acetate into black, it is a confirmatory test for sulphide ion.
Statement-II: In statement-I the colour of paper turns black because of formation of lead sulphite. In the light of the above statements, choose the most appropriate answer from the options given below:
Lassaigne's test is used for detection of :
Match List-I with the List-II
List-I
(Precipitating reagent and
conditions)		List-II
(Cation)
(A) \(NH_4Cl + NH_4OH\)(I) Mn2+
(B) \(NH_4OH + Na_2CO_3\)(II) Pb2+
(C) \(NH_4OH + NH_4Cl + H_2S gas\)(III) Al3+
(D) dilute HCl(IV) Sr2+
Choose the correct answer from the options given below:
Match List-I with List-II.
List-I
(Test)		List-II
(Identification)
(A) Bayer's test(I) Phenol
(B) Ceric ammonium nitrate test(II) Aldehyde
(C) Phthalein dye test(III) Alcoholic-OH group
(D) Schiff's test(IV) Unsaturation

Choose the correct answer from the options given below:
In qualitative test for identification of presence of phosphorous, the compound is heated with an oxidising agent. Which is further treated with nitric acid and ammonium molybdate respectively. The yellow coloured precipitate obtained is :
In a borax bead test under hot condition, a metal salt (one from the given) is heated at point B of the flame, resulted in green colour salt bead. The spin-only magnetic moment value of the salt is ............. BM (Nearest integer)
[Given atomic number of Cu = 29, Ni = 28,Mn = 25, Fe = 26]
Which of the following nitrogen containing compound does not give Lassaigne’s test ?
In the precipitation of the iron group (III) in qualitative analysis, ammonium chloride is added before adding ammonium hydroxide to :
Consider the following test for a group-IV cation. \[ \text{M}^{2+} + \text{H}_2\text{S} \rightarrow \text{A (Black precipitate)} + \text{byproduct} \] \[ \text{A + aqua regia} \rightarrow \text{B + NOCl + S + H}_2\text{O} \] \[ \text{B + KNO}_2 + \text{CH}_3\text{COOH} \rightarrow \text{C + byproduct} \] The spin-only magnetic moment value of the metal complex \( \text{C} \) is \( \dots \dots \dots \) BM. (Nearest integer)

The number of white coloured salts among the following is ___________.
(A) SrSO\(_4\), (B) Mg(NH\(_4\))PO\(_4\), (C) BaCrO\(_4\), (D) Mn(OH)\(_2\), (E) PbSO\(_4\), (F) PbCrO\(_4\), (G) AgBr, (H) PbI\(_2\), (I) CaC\(_2\)O\(_4\),(J) [Fe(OH)\(_2\)(CH\(_3\)COO)\(_2\)]

$\text{The oxidation number of iron in the compound formed during brown ring test for NO}_3^-\text{ ion is \_\_\_\_\_\_.}$
On passing a gas, ‘X’, through Nessler’s reagent, a brown precipitate is obtained. The gas ‘X’ is
A reagent which gives brilliant red precipitate with Nickel ions in basic medium is
In chromyl chloride test for confirmation of Cl-, a yellow solution is obtained. Acidification of the solution and addition of amyl alcohol and 10% H2O2​ turns organic layer blue indicating formation of chromium pentoxide. The oxidation state of chromium in that is
The Lassaigne’s extract is boiled with dil HNO\(_3\) before testing for halogens because
When a solution of mixture having two inorganic salts was treated with freshly prepared ferrous sulphate in acidic medium, a dark brown ferric ion was formed when treated with ferric chloride. It gave deep red colour which disappeared on boiling and a brown red ppt was formed. The mixture contains:
A white precipitate was formed when BaCl2 was added to water extract of an inorganic salt. Further, a gas ‘X’ with characteristic odour was released when the formed white precipitate was dissolved in dilute HCl. The anion present in the inorganic salt is

Consider the sulphides \( HgS, PbS, CuS, Sb_2S_3, As_2S_3 \) and \( CdS \). Number of these sulphides soluble in \( 50% \ HNO_3 \) is _____________