Alcohol, phenol & ether MCQs for NEET — Chemistry Questions with Answers

• 1,2- or vicinal diols are cleaved by periodic acid, HIO₄, into two carbonyl compounds.
• The reaction is selective for 1,2-diols.
• The reaction occurs via the formation of a cyclic periodate ester

HIO₄ will not oxidise, diol from 1, 3 atom & not used for cleavage of ether.

(c) 92g of a compound react with excess of CH₃Mgl to give x X 22400 mL of CH4 at STP.

   1 g of a compound react with excess of CH₃Mgl to give $\frac{\mathrm{x} \times 22400}{92}$

0.092 of a compound react with excess of CH₃Mgl tp give $\frac{\mathrm{x} \times 22400}{92}\times 0.092$ $$\begin{gathered} \frac{x \times 22400 0.092}{92}=67 \mathrm{mL} \mathrm{of} {\mathrm{CH}}_4 \mathrm{at} \mathrm{STP} \\ \mathrm{x}= \frac{67\times 92}{22400\times 0.092}=\frac{67\times 92\times 1000}{22400\times 92}=\frac{670}{224}=2.99\approx 3 \\ \mathrm{x}\Rightarrow \mathrm{number} \mathrm{of} \mathrm{active} \mathrm{hydrogen} \mathrm{in} \mathrm{compound}. \\ \mathrm{active} \mathrm{H}\Rightarrow 3 \end{gathered}$$

(c) C₂H₅OH gives iodoform test.

(b) Ethyl alcohol is mixed with methyl alcohol to denaturate it in order to prevent its use for drinking purposes.

(c) Alcohol forms a azeotropic mixture with water and absolute alcohol is obtained by this mixture (rectified spirit) by adding benzene and then carrying out fractional distillation.

(b) CH₃OH is toxic and injurious to health and therefore also used for denaturation of alcohol.

(c) -COOH$\stackrel{{\mathrm{LiAIH}}_4}{\to }$-CH₂OH

(d) Tertiary alcohols do not give Viktor Meyer's test.