For the following questions answer them individually
Consider two Group IV metal ious $$X^{2+}\text{ and }Y^{2+}$$
A solution containing $$0.01 M X^{2+}\text{ and }0.01MY^{2+}$$ is satmated with $$H_{2}S$$. The pH at which the metal sulphide YS will form as a precipitate is __ . (Nearest integer)
$$(Given:K_{sp}(XS)=1\times 10^{-22} \text{ at } 25^{\circ}C,K_{sp}(YS)=4\times 10^{-16} \text{ at } 25^{\circ}C,[H_{2}S]=0.1M\text{ in solution },K_{a1}\times K_{a2}(H_{2}S)=1.0\times 10^{-21},\log{2}=0.30,\log{3}=0.48,\log{5}=0.70)$$
In Dumas method for estimation of nitrogen, 0.50 g of an organic compound gave 70 mL of nitrogen collected at 300 K and 715 mm pressure. The percentage of nitrogen in the organic compound is __ %.
(Aqueous tension at 300 K is 15 mm).
X and Y are the number of electrons involved, respectively during the oxidation of $$\ I^{-}\text{ to }I_{2}\text{ and }S^{2-}$$ to S by acidified $$K_{2}Cr_{2}O_{7}$$. The value of X + Y is __ .
Electricity is passed through an acidic solution of $$Cu^{2+}$$ till all the Cu2+ was exhausted, leading to the deposition of 300 mg of Cu metal. However, a current of 600 mA was continued to pass through the same solution for another 28 minutes by keeping the total volume of the solution fixed at 200 mL. The total volume of oxygen evolved at STP during the entire process is __ mL. (Nearest integer)
[Given:
$$Cu^{2+}(aq)+2e^{-}\rightarrow Cu(s) E_{red}^{\circ}=+0.34V$$
$$O_{2}(g)+4H^{+}+4e^{-}\rightarrow 2H_{2}O E_{red}^{\circ}=+1.23V$$
Molar mass of Cu= 63.54 g $$mol^{-1}$$
Molar mass of $$O_{2}$$ = 32 g $$mol^{-1}$$
Farnday Constant = 96500 C $$mol^{-1}$$
Molar volume at STP = 22.4 L]
The hydrogen spectnun consists of several spectral lines in Lyman series ($$L_{1},L_{2},L_{3}....;L_{1}$$ has lowest energy among Lyman series). Similarly it consists of several spectral lines in Balmer series($$B_{1},B_{2},B_{3}....;B_{1}$$ has lowest energy among Balmer lines). The energy of $$L_{1}$$ is x times the energy of $$B_{1}$$. The value of x is_____ $$\times 10^{-1}$$. (Nearest integer)
