The equilibrium constant K_c at 298 K for the reaction A + B $$\rightleftharpoons$$ C + D is 100. Starting with an equimolar solution with concentrations of A, B, C and D all equal to 1M, the equilibrium concentration of D is ___________ $$\times$$ 10^$$-$$2 M. (Nearest integer)

For water $$\Delta$$_vap H = 41 kJ mol^$$-$$1 at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is ___________ kJ mol^$$-$$1

[Use : R = 8.3 J mol^$$-$$1 K^$$-$$1]

A metal surface is exposed to 500 nm radiation. The threshold frequency of the metal for photoelectric current is 4.3 $$\times$$ 10¹⁴ Hz. The velocity of ejected electron is ____________ $$\times$$ 10⁵ ms^$$-$$1 (Nearest integer)

[Use : h = 6.63 $$\times$$ 10^$$-$$34 Js, m_e = 9.0 $$\times$$ 10^$$-$$31 kg]

For the galvanic cell,

Zn(s) + Cu²⁺ (0.02 M) $$\to$$ Zn²⁺ (0.04 M) + Cu(s),

E_cell = ______________ $$\times$$ 10^$$-$$2 V. (Nearest integer)

[Use : $$E_{Cu/C{u^{2 + }}}^0$$ = $$-$$ 0.34 V, $$E_{Zn/Z{n^{2 + }}}^0$$ = + 0.76 V, $${{2.303RT} \over F} = 0.059\,V$$]