p-Block Elements · Chemistry · COMEDK

Choose the pair of elements $[(\mathrm{A})$ to $(\mathrm{F})]$ which:

(i) belong to the Chalcogen family

(ii) form monovalent oxides which give alkalies in aqueous solution

(iii) form stable monovalent anions

(A) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^1$

(B) $1 s^2 2 s^2 2 p^5$

(C) $1 s^2 2 s^2 2 p^6 3 s^1$

(D) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^5$

(E) $1 s^2 2 s^2 2 p^6 3 s^2 3 p^4$

(F) $1 s^2 2 s^2 2 p^4$

Given are $$\mathrm{H}_3 \mathrm{PO}_2, \mathrm{H}_3 \mathrm{PO}_3, \mathrm{H}_3 \mathrm{PO}_4$$ and $$\mathrm{H}_4 \mathrm{P}_2 \mathrm{O}_7$$. Which of the above oxacids results into two series of salts?

The order of acidic strength of boron trihalides is

Give the correct order of acidity of

The cololur of CrO$$_4^{2-}$$ changes to Cr$$_2$$O$$_7^{2-}$$ is

Arrange the hydrides of group 15 in correct decreasing order of reducing nature.

When conc. H$$_2$$SO$$_4$$ is heated with P$$_2$$O$$_5$$, the acid is converted into