Hydrocarbons Question 262
Question: Which of the following compounds is used in antiknock compositions to prevent the deposition of oxides of lead on spark plug, combustion chamber and exhaust pipe [KCET 1998]
Options:
A) Glycerol
B) Glycol
C) 1, 2-dibromoethane
D) Benzene
Show Answer
Answer:
Correct Answer: C
Solution:
$ Pb{{(C_2H_5)}_4}\xrightarrow{heat}Pb+\underset{Ethylradical}{\mathop{4CH_3CH_2^{{}}}} $
$ \underset{\underset{Br}{\mathop{|}}}{\mathop{CH_2}}-\underset{\underset{Br}{\mathop{|}}}{\mathop{CH_2}}+Pb\xrightarrow{{}}\underset{Ethene}{\mathop{CH_2=CH_2}}+\underset{\text{Lead bromide}}{\mathop{PbBr_2}} $ As leaded gasoline burns, lead metal gets deposited in the engine which is removed by adding ethylene dibromide.
The lead bromide is volatile and is carried off with the exhaust gases from the engine
BETA
