$$ \text { Arrange the following carbanions in the decreasing order of stability. } $$

Choose the correct answer from the options given below :

At $27^{\circ} \mathrm{C}$ in presence of a catalyst, activation energy of a reaction is lowered by $10 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The logarithm of ratio of $\frac{\mathrm{k} \text { (catalysed) }}{\mathrm{k} \text { (uncatalysed) }}$ is….

(Consider that the frequency factor for both the reactions is same)

A student is given one compound among the following compounds that gives positive test with Tollen's reagent.

The compound is :

Consider three metal chlorides $\mathrm{x}, \mathrm{y}$ and z , where x is water soluble at room temperature, y is sparingly soluble in water at room temperature and z is soluble in hot water. $\mathrm{x}, \mathrm{y}$ and z are respectively