The number of possible alkyns with molecular formula C₅H₈ is

• 3

• 4

• 5

• 6

A metal 'M' reacts with N₂ to give a compound 'A' (M₃N). 'A' on heating at high temperature gives back 'M' and 'A' on reacting with H₂O give a gas B. 'B' turns CuSO₄ solution blue on passing through it. M and B can be

• Al and NH₃

• Li and NH₃

• Na and NH₃

• Mg and NH₃

Plaster of Paris on making paste with little water sets to hard mass due to formation of

• CaSO₄

• CaSO₄.1/2 H₂O

• CaSO₄ H₂O

• CaSO₄.2H₂O

C-C bond length is maximum in

• diamond

• graphite

• naphthalene

• fullerone

Ammoniacal silver nitrate form a white precipitate easily with

• CH₃C≡CH

• CH₃C≡C-CH₃

• CH₃CH=CH₂

• CH₂=CH₂

A solution of sodium thiosulphate on addition of few drops of ferric chloride gives violet colour due to the formation of

• Na₂S₄O₆

• Fe₂(SO₄)₃

• Fe₂(S₂O₃)₃

• Fe₂(S₂O₃)₂

47.

pH of a 0.0001M HCl solution is

• 4.0

• 2.0

• 6.0

• 7.0

A reaction proceeds by first order, 75% of this reaction was completed in 32 min. The time required for 50% completion is

• 8 min

• 16 min

• 20 min

• 24 min

Aqueous solution of ferric chloride is acidic due to

• ionization

• polarization

• dissociation

• hydrolysis

The correct order of heat of formation of halogen acids is

• HI > HBr > HCl > HF

• HF > HCl > HBr > HI

• HCl > HF > HBr > HI

• HCl > HBr > HF > HI