Question

A carbon compound ' P' on heating with excess conc. H2SO4 forms anothe carbon compound 'Q' which on addition of hydrogen in the presence of nickel catalyst forms a saturated carbon compound 'R' . One molecule of 'R' on combustion forms two molecules of carbon dioxide and three molecules of water. Identify 'P' , 'Q' , ' R' and write chemical equation for the reaction involved.

Answer 1

P-Ethanol
Q-Ethene
R- Ethane

Answer 2

Given:- Compound P having two carbon atoms

And Q is a carbon compound which on addition of hydrogen give saturated compound.

R is a saturated compound.

To find:- P, Q and R

Solution:-

- P is an alcohol which on heating with excess of concentated H2SO4 forms another carbon compound Q which is an unsaturated compound. This reaction shows dehydration.

presence of the catalyst Q phones a saturated compound. Therefore Q will be an unsaturated compound which is an alkene(Ethene)

- The reaction is given below:-

(i) CH3CH2OH + H2SO4  → CH2= CH2+ H2O

(Dehydration of alcohol)

- Q(Ethene) which is an unsaturated compound which on addition of hydrogen in presence of nickel catalyist forms a saturated compound R which is ethane.

- The reaction is:-

CH2= CH2 + H2 ----Ni---->C2H6(Ni catalyst)

- One molecule of R(Ethane) which on combustiin forms two molecules of carbon dioxide and three molecules of water.

- The reaction is:-

C2H6 + O2 → 2CO2 + 3H2O

- Thus,

P => CH3CH2OH

Q =>CH2 = CH2

R => CH3CH3