An aqueous solution of a salt MX₂ at certain temperature has a van’t Hoff factor of 2. The degree of dissociation for this solution of the salt is :

Which one of the following reagents is not suitable for the elimination reaction ?

The volume of 0.1N dibasic acid sufficient to neutralize 1 g of a base that furnishes 0.04 mole of OH⁻ in aqueous solution is :

$$\mathop {\lim }\limits_{x \to 0} \,{{{{\left( {1 - \cos 2x} \right)}^2}} \over {2x\,\tan x\, - x\tan 2x}}$$ is :