Question

how will you convert acetone into propane

Answer 1

we can convert acetone in to propane by reduction using Zn/Hg/HCl .This is known as Clemmensen's reduction.
CH3-CO-CH3 IN presence of that reagent the CO group convert in to CH2.then it become CH3-CH2-CH3.

Answer 2

Answer : By the Clemmenen reduction we can convert acetone into propane.

Explanation :

Clemmenen reduction :

The carbonyl compounds on reduction with zinc amalgam (Zn-Hg) in the presence of hydrochloric acid result in the formation of alkanes. In this reaction, the carbonyl group converted into $CH_2$ group and result in the formation of alkanes.

The reaction are shown below.