$15 \text{ mL}$ of aqueous solution of $Fe^{2+}$ in acidic medium completely reacted with $20 \text{ mL}$ of $0.03 \text{ M}$ aqueous $Cr_2O_7^{2-}$. The molarity of the $Fe^{2+}$ solution is $\times 10^{-2} \text{ M}$ (Round off to the Nearest Integer).

If $\frac{3x}{(x-a)(x-b)} = \frac{2}{x-a} + \frac{1}{x-b}$,then $a:b$ is equal to

Select the wrong statement.

Which of the following pairs of orbitals possess two nodal planes?

Aqueous solutions of two compounds $M_1-OH$ and $M_2-OH$ are prepared in two different beakers. If the electronegativity of $M_1 = 3.4, M_2 = 1.2, O = 3.5$ and $H = 2.1$,then the nature of the two solutions will be respectively:

Consider the following statements for $X = \dot{C}H_3$ and $Y = \dot{C}F_3$:
$(I)$ When $X$ dimerises,the bond angle decreases.
$(II)$ When $X$ dimerises,the bond angle increases.
$(III)$ In the $X-Y$ molecule,the $C-C$ bond length is less than that in the $Y-Y$ molecule.
$(IV)$ The bond angle in $X$ is greater than that in $Y$.