A set of solutions is prepared using 180 g of water as a solvent and 10 g of different nonvolatile solutes A, B and C. The relative lowering of vapour pressure in the presence of these solutes are in the order :

[Given, molar mass of A = 100 g mol^–1; B = 200 g mol^–1; C = 10,000 g mol^–1]

For the given cell :

Cu(s) | Cu²⁺(C₁M) || Cu²⁺(C₂M) | Cu(s)

change in Gibbs energy ($$\Delta $$G) is negative, if :

Which one of the following statements is not true?

For a suitably chosen real constant a, let a

function, $$f:R - \left\{ { - a} \right\} \to R$$ be defined by

$$f(x) = {{a - x} \over {a + x}}$$. Further suppose that for any real number $$x \ne - a$$ and $$f(x) \ne - a$$,

(fof)(x) = x. Then $$f\left( { - {1 \over 2}} \right)$$ is equal to :