Which of the following substances is a deliquescent ionic solid?

Which one of the following cannot form an amphoteric oxide?

Which of the following are the correct orders of stability of oxidation states of cations?
$(a) \ Pb^{+2} > Pb^{+4}, Tl^{+1} < Tl^{+3}$
$(b) \ Bi^{+3} < Sb^{+3}, Sn^{+2} < Sn^{+4}$
$(c) \ Pb^{+2} > Pb^{+4}, Bi^{+3} > Bi^{+5}$
$(d) \ Tl^{+3} < In^{+3}, Sn^{+2} > Sn^{+4}$
$(e) \ Sn^{+2} < Pb^{+2}, Sn^{+4} > Pb^{+4}$
$(f) \ Sn^{+2} < Pb^{+2}, Sn^{+4} < Pb^{+4}$

What is the correct order of acidic character for the given oxides?

Which of the following is a cyclic phosphate?

$A$ group $15$ element forms $d \pi - d \pi$ bond with transition metals. It also forms a hydride,which is the strongest base among the hydrides of other group members that form $d \pi - d \pi$ bonds. The atomic number of the element is $.......$