$XeO_4$ molecule is tetrahedral having

Under which of the following conditions will a convex mirror of focal length $f$ produce an image that is erect,diminished and virtual?

Which of the following gases has the highest heat of combustion?

The molecular formula of diphenylmethane is $C_{13}H_{12}$. How many structural isomers are possible when one of the hydrogen atoms is replaced by a chlorine atom?

Three perfect gases at absolute temperatures $T_1, T_2$ and $T_3$ are mixed. The masses of molecules are $m_1, m_2$ and $m_3$ and the number of molecules are $n_1, n_2$ and $n_3$ respectively. Assuming no loss of energy,the final temperature of the mixture is

The branch of botany that deals with the study of algae is known as: