In the following sub questions choose the correct answer from among the following possibilities and express the final answer as sum of the numbers
(P) The most stable low valent halide $\text{ (1) }{\mathrm{GeX}}_2\text{ (2) }{\mathrm{SnX}}_2\text{ (3) }{\mathrm{PbX}}_2$
(Q) A non existing halide $\text{ (1) }{\mathrm{SnCl}}_4\text{ (2) }{\mathrm{PbCl}}_4\text{ (3) }{\mathrm{PbI}}_4$
(R) A purely acidic oxide $\text{ (1) }{\mathrm{PbO}}_2\text{ (2) }{\mathrm{SnO}}_2\text{ (3) }{\mathrm{SiO}}_2$
(S) Thermally most stable hydride $\text{ (1) }{\mathrm{NH}}_3\left(2\right){\mathrm{PH}}_3\text{ (3) }{\mathrm{AsH}}_3$