What is the total number of electrons present in bonding orbitals of $\mathrm{O}_2$ molecule according to molecular orbital theory?

Calculate the relative lowering of vapour pressure of solution containing 46 g of non volatile solute in 162 g of water at $20^{\circ} \mathrm{C}$. [Molar mass of nonvolatile solute $=46 \mathrm{~g} \mathrm{~mol}^{-1}$]

Identify acidic amino acid from following (represented by using three letter symbols)

Let $A=\left[\begin{array}{ll}x & 1 \\ 1 & 0\end{array}\right], x \in \mathbb{R}^{+}$and $A^4=\left[a_{i j}\right]_2$. If $a_{11}=109$, then $\left(A^4\right)^{-1}=$