Bond energy of covalent $O-H$ bond in water is

When acetylene is passed through a red-hot iron tube,compound $X$ is formed. Which one of the following reactions will yield $X$ as the major product?

Two sound waves of slightly different frequencies propagating in the same direction produce beats due to

Let $f(x) = \int \frac{\sqrt{x}}{(1+x)^2} \, dx, x \geq 0$. Then $f(3) - f(1)$ is equal to

The displacement-time graph for two particles $A$ and $B$ are straight lines inclined at angles of $30^o$ and $60^o$ with the time axis. The ratio of velocities of $V_A : V_B$ is

Which one of the following pairs is mismatched?