In diborane,the $H-B-H$ bond angle is $120^o$. The hybridization of boron is likely to be

Which of the following statements is incorrect?

$A$ black coloured element with $ns^2 np^1$ outer electronic configuration cannot react with air in its crystalline form. However, in amorphous form, it gives an oxide in air which is acidic in nature. Identify the element.

Sodium borohydride upon treatment with iodine produces a Lewis acid $(X)$,which on heating with ammonia produces a cyclic compound $(Y)$ and a colourless gas $(Z)$. $X, Y$ and $Z$ are $....$

When an excess of $NaOH$ solution is added to a solution of potassium alum,what do we obtain?

Which of the following substances is the strongest acid?