Which of the following can be added to remove the permanent hardness of water?

Which chemical is associated with flowering?

If $f(x)=2 x^4-13 x^2+a x+b$ is divisible by $x^2-3 x+2$,then $(a, b)$ is equal to

Which of the following statements is not true?

This is the $1^{st}$ and $2^{nd}$ exam question.

$BX_3 + NH_3 \xrightarrow{R.T} BX_3 \cdot NH_3 + \text{Heat of adduct formation } (\Delta H)$. The numerical value of $\Delta H$ is found to be maximum for: