Question

10 ml of gaseous hydrcarbon is exploded with 100 ml O2. The residual gas on cooling is found to measure 95 ml of which 20 ml is abosrbed by KOH and the reminder by alkaline pyrogallol. The formula of the hydrocarbon is :

Answer 1

Question:

10 ml of gaseous hydrcarbon is exploded with 100 ml O2. The residual gas on cooling is found to measure 95 ml of which 20 ml is abosrbed by KOH and the reminder by alkaline pyrogallol. The formula of the hydrocarbon is :

Solution:

Volume of CO2 = 20 ml (absorbed gas by KOH)

Volume of air unreacted = 95 – 20 = 75 (gas abosrbed by pyrogallol)

then, O2 reacted = 100 + 75 = 25 ml

∵ 10 ml hydrocarbon libarates 20 ml CO2.

∴ 2 atoms of ‘C’ are present in the compound.

or,          C2Hx    +    yO2 →   2CO2    +   H2O

initial       10 ml        25 ml

final           0             0              20             10 ml

volume of water vapours = (25 – 20) × 2 = 10 ml

∵ 10 ml hydrocarbon gives 10 ml water vapours.

∴ No. of Hydrogen atoms in compounds are 2.

∴ Compound will be C2H2.

Answer 2

Answer:

Pyrogallate of potash

Explanation: