Bleaching powder is obtained by treating chlorine with

The oxide,which is best soluble in $H_2O$ is

Among the following,which is water insoluble?

$CO_2$ is passed through lime water. Initially,the solution turns milky and then becomes clear upon continued bubbling of $CO_2$. The clear solution is due to the formation of:

Which of the following elements is chemically most reactive?

The setting time of cement is increased by adding which of the following?