Question

Which of the following is not correct about methanol?
A. It is used for drinking purpose
B. It is a highly poisonous compound
C. It can be prepared by reduction of formaldehyde with \[\text{LiAl}{{\text{H}}_{4}}\].
D. It is miscible with water in all-purpose

Answer 1

Hint: Methanol which is also known as methyl alcohol is a colourless and toxic liquid. Methanol can affect the central nervous system for our mind. Lithium aluminium hydride is a strong reducing agent and it can reduce the formaldehyde. Methanol is a polar substance.

Complete answer:
-Methanol has a chemical formula of $\text{C}{{\text{H}}_{3}}\text{OH}$ and it is not considered for the drinking purpose because methanol is highly toxic.
-If anyone is exposed to the methanol vapours or consumed by anyone then it may be fatal and adversely affect the central nervous system present in the body.
-This is caused because when methanol is metabolised by the body then it forms a highly toxic compound known as formic acid.
-So, methanol is not used for the drinking purpose due to its poisonous nature.
-Hence, option B is the correct statement.
-Option C is also a correct statement because methanol can be prepared by reducing the formaldehyde with the help of lithium aluminium hydride.
-As we know that lithium aluminium hydride is a strong reducing agent. So, in the reduction process, the double- bond between oxygen and carbon breaks and a hydrogen atom attached to it.
$\begin{align}
  & \text{H - CHO }\xrightarrow{\text{LiAl}{{\text{H}}_{4}}}\text{ C}{{\text{H}}_{3}}\text{OH} \\
 & \text{(Formaldehyde) (Methanol)} \\
\end{align}$
-Option D is also correct because methanol is soluble in water under all conditions. After all, methanol is polar and water is also polar.
-So, according to 'Like Dissolve Like' they are soluble in the water and also the OH group have more affinity for the water to make bond.
So, the correct answer is “Option A”.

Note: The solubility of the three compounds of the alcohol is that they are miscible in water because they are polar but as the chain increases by the addition of methyl group the solubility also decreases.