Hydrocarbons - Result Question 90

78. Following statements are true, only under some specific conditions. Write the condition for each subquestion in not more than two sentences :

(i) $2$-methyl propene can be converted into isobutyl bromide by hydrogen bromide.

(ii) Ethyne and its derivatives will give white precipitate with ammoniacal silver nitrate solution.

$(1984,1 M \times 2=2 M)$

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Solution:

  1. (i)

In the absence of peroxide, $HBr$ would be added giving tertiary butyl bromide.

(ii) Tertiary alkynes are slightly acidic, forms silver salt with ammoniacal solution of silver nitrate :

$R-C \equiv C-H+AgNO _3 \xrightarrow{NH _3(a q)} R- \underset{\text{White ppt.}}{C \equiv CAg} \downarrow$