Chemistry MCQS

351. Which one of the following does not give Lassaigne’s test for nitrogen?
(A) Glycine
(B) Phenyl Hydrazine
(C) Urea
D) Hydroxylamine

352. Which compound decolorizes KMnO₄ solution but does not give a test with AgNO₃ solution?
(A) Acetylene
B) Ethylene
(C) Ethane
(D) None of the above

353. Weakest base is?
(A) H
B) Cl
(C) HCO₃
(D) OH

354. Phenolphthalein is colorless in acidic medium due to?
(A) Nitric acid
(B) Sulphur
C) Benzenoid form
(D) None of the above

355. The equilibrium constant (Kc) for the reaction: N₂ + 3H₂ ⇌ 2NH₃ is:
A. [NH₃] / [N₂] × [H₂]³
B. [NH₃] / [N₂] + [H₂]³
C. [N₂] × [H₂]³ / [NH₃]
D. [N₂] + [H₂]³ / [NH₃]

356. The equilibrium constant (Kc) for the reaction: CO + H₂O ⇌ CO₂ + H₂ is:
A. [CO₂] × [H₂] / [CO] × [H₂O]
B. [CO₂] × [H₂O] / [CO] × [H₂]
C. [CO] × [H₂] / [CO₂] × [H₂O]
D. [CO] × [H₂O] / [CO₂] × [H₂]

357. The equilibrium constant (Kc) for the reaction: N₂O₄ ⇌ 2NO₂ is:
A. [NO₂] / [N₂O₄]²
B. [N₂O₄] / [NO₂]²
C. [NO₂]² / [N₂O₄]
D. [N₂O₄]² / [NO₂]

358. If the concentration of products is increased, the equilibrium will shift in the direction of:
A. Reactants
B. Products
C. No change in equilibrium position
D. Both reactants and products in equal amounts

359. Le Chatelier’s principle states that when a system at equilibrium is subjected to a change in temperature, pressure, or concentration of reactants or products, the system will:
A. Remain unchanged
B. Shift to the left
C. Shift to the right
D. Completely react to form products

360. The equilibrium constant (Kc) for the reaction: 2SO₂ + O₂ ⇌ 2SO₃ is:
A. [SO₃]² / [SO₂] × [O₂]
B. [SO₂] × [O₂] / [SO₃]²
C. [SO₃] × [SO₂] / [O₂]²
D. [SO₂] × [O₂]² / [SO₃]