Modern farmers have been able to increase rice production by $50\%$ using which of the following?

One hundred identical coins,each with probability $p$ of showing heads,are tossed once. If $0 < p < 1$ and the probability of heads showing on $50$ coins is equal to that of heads showing on $51$ coins,then the value of $p$ is

$\sinh^{-1}\left(\frac{x}{\sqrt{1-x^2}}\right)$ is equal to

Which of the following compounds will be most easily attacked by an electrophile?

Which of the following reacts with benzene in the presence of anhydrous aluminum chloride to form acetophenone?

If $ab \neq 0$ and the sum of the coefficients of $x^7$ and $x^4$ in the expansion of $\left(\frac{x^2}{a}-\frac{b}{x}\right)^{11}$ is $0$,then