The compound of copper which turns green on keeping in air is

The number of ionisable hydrogens present in the product obtained from a reaction of phosphorus trichloride $(PCl_3)$ and phosphonic acid $(H_3PO_3)$ is

$CO_2$ and $N_2$ do not support combustion. However,$CO_2$ is preferred over $N_2$ for extinguishing fires because $CO_2$ .......

Which of the following is the pyrosilicate ion?

What is meant by $Tin \ Plague$?

Reaction of an inorganic sulphite $X$ with dilute $H_{2}SO_{4}$ generates compound $Y$. Reaction of $Y$ with $NaOH$ gives $X$. Further,the reaction of $X$ with $Y$ and water affords compound $Z$. $Y$ and $Z$,respectively,are: