The oxidation states of iron atoms in compounds (A), (B) and (C), respectively, are x, y and z. The sum of x, y and z is ________.

Na₄[Fe(CN)₅(NOS)]
       (A)

Na₄[FeO₄]
       (B)

[Fe₂(CO)₉]
       (C)

The internal energy change (in J) When 90 g of water undergoes complete evaporation at 100^oC is ____________.

(Given : $$\Delta $$H_vap for water at 373 K = 41 kJ/mol,
R = 8.314 JK^–1 mol^–1)

If |x| < 1, |y| < 1 and x $$ \ne $$ y, then the sum to infinity of the following series

(x + y) + (x²+xy+y²) + (x³+x²y + xy²+y³) + ....

Let $$\alpha $$ > 0, $$\beta $$ > 0 be such that
$$\alpha $$³ + $$\beta $$² = 4. If the maximum value of the term independent of x in
the binomial expansion of $${\left( {\alpha {x^{{1 \over 9}}} + \beta {x^{ - {1 \over 6}}}} \right)^{10}}$$ is 10k,
then k is equal to :