Detection of nitrogen, sulphur, phosphorus and halogens — NEET & JEE Questions

Question 1 · difficulty L1 · recall

In Lassaigne's test, covalently bound nitrogen, sulphur and halogens are converted into

• A. water-soluble ionic sodium salts
• B. volatile hydrocarbons
• C. metallic elements
• D. insoluble oxides only

Question 2 · difficulty L2 · understanding

$$\text { Match the LIST-I with LIST-II }$$ List - I List - II Compound Test A. I. Hinsberg's reagent test B. II. Phthalein dye test C. III. Lucas test D. IV. Tollen’s test $$\text { Choose the correct answer from the options given below : }$$

• A. A-III, B-I, C-IV, D-II
• B. A-III, B-IV, C-I, D-II
• C. A-I, B-III, C-II, D-IV
• D. A-I, B-II, C-III, D-IV

Question 3 · difficulty L2 · understanding

Complete combustion of $X$ g of an organic compound gave $0.25$ g of $CO_2$ and $0.12$ g of $H_2O$. If the % of carbon is $25\%$ and of hydrogen is $4.89\%$, then $X = \underline{\phantom{xxx}} \times 10^{-3}$ g. (Nearest integer) (Molar mass of C, H and O are 12, 1 and 16 g mol$^{-1}$ respectively.)

• A. 273
• B. 27
• C. 2730
• D. 227

Question 4 · difficulty L2 · understanding

Match List - I with List - II . List - I Mixture of Compounds List - II Reagent used to distinguish A Diethyl amine + Ethyl amine I Bromine water B Acetaldehyde + Acetone II CHCl₃ + KOH, Δ C Ethanol + Phenol III Neutral FeCl₃ D Benzoic acid + Cinnamic acid IV Ammoniacal silver nitrate Choose the correct answer from the options given below :

• A. A-IV, B-II, C-I, D-III
• B. A-IV, B-II, C-III, D-I
• C. A-II, B-IV, C-I, D-III
• D. A-II, B-IV, C-III, D-I

Question 5 · difficulty L2 · understanding

$$\text { Match List - I with List - II. }$$ List - I Functional group (detection) List - II Change observed during detection A. Unsaturation (Baeyer's test) I. Red colour appears B. Alcoholic group (Ceric ammonium nitrate test) II. Silver mirror appears C. Aldehyde group (Tollen's reagent) III. Violet colour appears D. Phenolic group ( $\mathrm{FeCl}_3$ test) IV. Discharge of pink colour

• A. A-IV, B-I, C-II, D-III
• B. A-III, B-IV, C-I, D-II
• C. A-III, B-IV, C-II, D-I
• D. A-IV, B-III, C-II, D-I

Question 6 · difficulty L2 · understanding

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 :

• A. (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
• B. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
• C. (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
• D. (A)-(IV), (B)-(III), (C)-(I), (D)-(II)

Question 7 · difficulty L2 · understanding

Match List I with List II LIST I Element detected LIST II Reagent used / Product formed A. Nitrogen I. $$\mathrm{Na_2[Fe(CN)_5NO]}$$ B. Sulphur II. $$\mathrm{AgNO_3}$$ C. Phosphorous III. $$\mathrm{Fe_4[Fe(CN)_6]_3}$$ D. Halogen IV. $$\mathrm{(NH_4)_2MoO_4}$$ Choose the correct answer from the options given below:

• A. A-III, B-I, C-IV, D-II
• B. A-II, B-I, C-IV, D-III
• C. A-IV, B-II, C-I, D-III
• D. A-II, B-IV, C-I, D-III

Question 8 · difficulty L2 · understanding

Given below are two statements : Statement I : Sulphanilic acid gives esterification test for carboxyl group. Statement II : Sulphanilic acid gives red colour in Lassigne's test for extra element detection. In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both Statement I and Statement II are correct
• B. Statement I is correct but Statement II is incorrect
• C. Both Statement I and Statement II are incorrect
• D. Statement I is incorrect but Statement II is correct

Question 9 · difficulty L2 · understanding

In Dumas method for the estimation of $\mathrm{N}_{2}$, the sample is heated with copper oxide and the gas evolved is passed over :

• A. Copper oxide
• B. Copper gauze
• C. $\mathrm{Pd}$
• D. $\mathrm{Ni}$

Question 10 · difficulty L2 · understanding

Compound that will give positive Lassaigne's test for both nitrogen and halogen is :

• A. $$\mathrm{NH_2OH.HCl}$$
• B. $$\mathrm{N_2H_4.HCl}$$
• C. $$\mathrm{CH_3NH_2.HCl}$$
• D. $$\mathrm{NH_4Cl}$$