The cell potential for the following cell

Pt |H₂(g)|H⁺ (aq)|| Cu²⁺ (0.01 M)|Cu(s)

is 0.576 V at 298 K. The pH of the solution is __________. (Nearest integer)

(Given : $$E_{C{u^{2 + }}/Cu}^o = 0.34$$ V and $${{2.303\,RT} \over F} = 0.06$$ V)

The rate constants for decomposition of acetaldehyde have been measured over the temperature range 700 - 1000 K. The data has been analysed by plotting ln k vs $${{{{10}^3}} \over T}$$ graph. The value of activation energy for the reaction is ___________ kJ mol^$$-$$1. (Nearest integer)

(Given : R = 8.31 J K^$$-$$1 mol^$$-$$1)

The difference in oxidation state of chromium in chromate and dichromate salts is ___________.

In the cobalt-carbonyl complex : [Co₂(CO)₈], number of Co-Co bonds is "X" and terminal CO ligands is "Y". X + Y = ___________.