Cyclic hydrocarbon molecule $A$ has all the carbon and hydrogen atoms in a single plane. All the carbon-carbon bonds are of the same length,which is less than $1.54 \ \mathring{A}$ but more than $1.34 \ \mathring{A}$. The $C-C$ bond angle will be

$A$ monoatomic ideal gas,initially at temperature $T_1$,is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature $T_2$ by releasing the piston suddenly. If $L_1$ and $L_2$ are the lengths of the gas column before and after expansion respectively,then $T_1/T_2$ is given by

Which of the following statements is correct?

To distinguish between $A$ and $B$,it is observed that both elements form oxides. When burnt in air,$B$ also forms a nitride. What are $A$ and $B$?

Which of the following statements is not correct?

Which of the following statements are correct about herbarium?