Which one of the following is a stimulant?

Assertion $(A)$: $A$ catalyst increases the rate of a reaction.
Reason $(R)$: In the presence of a catalyst,the activation energy of the reaction increases.
The correct answer is

If the image of $\left(\frac{-7}{5}, \frac{-6}{5}\right)$ in a line is $(1, 2)$,then the equation of the line is

Nitrobenzene on reduction with zinc and $NH_4Cl$ gives

If $A$ is a square matrix of order $3$,then $|\operatorname{adj}(\operatorname{adj} A^2)|$ is equal to

The experimentally determined molar mass of a non-volatile solute,$BaCl_2$,in water by Cottrell's method,is