Which of the following is not correctly matched?

The keys are based on contrasting characters generally in a pair called . . . . . . .

$A$ uniform metal rod of $2\,mm^2$ cross-section fixed between two walls is heated from $0\,^{\circ}C$ to $20\,^{\circ}C$. The coefficient of linear expansion of the rod is $12 \times 10^{-6}\,/^{\circ}C$. Its Young's modulus of elasticity is $10^{11}\,N/m^2$. The energy stored per unit volume of the rod will be ....... $J/m^3$.

$CFCl_3$ is responsible for the decomposition of ozone to oxygen. Which of the following reacts with ozone to form oxygen?

The number of ways that $8$ beads of different colours can be strung as a necklace is

Which of the following equilibria will shift to the right side on increasing the temperature?