Exams › JEE Advanced › Chemistry

A salt sample gives the following test results: - Flame test: Golden yellow flame - conc. H2SO4 / MnO2: Gas (X) — greenish-yellow - AgNO3 solution: Precipitate (Z) — white, insoluble in dilute HNO3 - K2Cr2O7 / conc. H2SO4: Vapour (Y) — reddish-brown Which of the following statements about X, Y, Z is INCORRECT?

1. (X) can be formed by oxidation of HCl with O2 in the presence of CuCl2 as catalyst
2. When (Y) is passed into NaOH solution, a yellow solution is formed
3. (Z) does not give the chromyl chloride test
4. (X) when reacted with excess of NH3, then one of the diamagnetic products becomes paramagnetic

Correct answer: (X) when reacted with excess of NH3, then one of the diamagnetic products becomes paramagnetic

Solution

The salt is NaCl (golden yellow flame = Na+, Cl- gives all the reactions). X = Cl2 (greenish-yellow, from HCl + MnO2 or from Deacon process with CuCl2 catalyst — statement A is correct). Y = CrO2Cl2 (chromyl chloride, reddish-brown; dissolves in NaOH to give yellow chromate solution — statement B is correct). Z = AgCl (white, insoluble in dil HNO3; AgCl itself does NOT give chromyl chloride test since it cannot react with K2Cr2O7/H2SO4 to give CrO2Cl2 from AgCl — wait, Z is the precipitate of AgCl which would not give the test separately — statement C is correct). For D: Cl2 + excess NH3 gives NH4Cl and N2. NH4Cl is diamagnetic, N2 is diamagnetic. No paramagnetic product — so saying one diamagnetic product becomes paramagnetic is INCORRECT.

Related JEE Advanced Chemistry questions

• When carbonates from the s-block break down, a gas is released that is denser than air and extinguishes a burning splint. Identify the gas.
• What is the classification of Be2C and Al4C3 based on their chemical composition?
• When heated, magnesium nitrate and barium nitrate break down as follows: 2M(NO3)2 → heat → 2MO + 4NO2(g) + O2(g) (where M = Mg or Ba). Which statement is accurate regarding their decomposition behavior?
• Consider the following reactions of Group IA (alkali) metals with liquid ammonia: M + (x+y) NH3 -> [M(NH3)ₓ]+ + [e(NH3)_y]- [M(NH3)ₓ]+ + e-(in NH3) -> M-NH2(aq) + (1/2) H2(g) Which of the following statements about these solutions is INCORRECT?
• How many of the following elements give a characteristic flame test color: Li, Na, K, Be, Mg, Ca, Ba, Cs?
• Arrange the following carbonates in the correct increasing order of their thermal stability: BeCO3, MgCO3, CaCO3, K2CO3.

⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →