Which of the following alloys contains a non-metal?

Slow acting nitrogenous fertilizer among the following is

Which of the following statements is correct?

What is the chemical formula for green vitriol?

Select the incorrect order for the given properties:
$(a)$ $A_2B < AB < A_2B_3 = \text{Lattice Energy (L.E.)}$ (Charge of $B = -2$)
$(b)$ $Na_2CO_3 < K_2CO_3 < Rb_2CO_3 < Cs_2CO_3 = \text{Thermal stability}$
$(c)$ $MgF_2 < CaF_2 < SrF_2 < BaF_2 < BeF_2 = \text{Solubility}$
$(d)$ $LiOH < NaOH < KOH < RbOH < CsOH = \text{Solubility and stability}$

The alloy used in the construction of aircraft is