Question

a carbon compound 'P' on heating with excess conc. h2so4 forms another 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 and R and write chemical equations for the reactions involved.

Answer 1

P is ethanol. Q is ethene. R is ethane 

1.C2H5OH+H2SO4--->C2H4+H2O 

2.C2H4+H2--------Ni----->C2H6 . (Ni=nickel as catalyst)

3.C2H6+O2---------->2CO2+3H2O


hope this helps!! cheers!! (:

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*