Among the following oxides of $p$-block elements,the number of oxides having amphoteric nature is: $Cl_2O_7, CO, PbO_2, N_2O, NO, Al_2O_3, SiO_2, N_2O_5, SnO_2$

Assertion : Stannous chloride gives grey precipitate with mercuric chloride,but stannic chloride does not do so.
Reason : Stannous chloride is a powerful oxidising agent which oxidises mercuric chloride to metallic mercury.

Which of the following products is formed on boiling tin with an alkali solution?

Which of the following statements is correct with respect to the property of elements with an increase in atomic number in the carbon family (group $14$)?

At high temperature,nitrogen combines with $CaC_2$ to give:

Number of oxygen atoms present in the chemical formula of fuming sulphuric acid is . . . . .