The sum of oxidation states of two silver ions in [Ag(NH₃)₂] [Ag(CN)₂] complex is _____________.

The number of atoms in 8g of sodium is x $$\times$$ 10²³. The value of x is ____________. (Nearest integer)

[Given : N_A = 6.02 $$\times$$ 10²³ mol^$$-$$1

Atomic mass of Na = 23.0 u]

If 80 g of copper sulphate CuSO₄ . 5H₂O is dissolved in deionised water to make 5L of solution. The concentration of the copper sulphate solution is x $$\times$$ 10^$$-$$3 mol L^$$-$$1. The value of x is _____________.

[Atomic masses Cu : 63.54u, S : 32u, O : 16u, H : 1u]

A 50 watt bulb emits monochromatic red light of wavelength of 795 nm. The number of photons emitted per second by the bulb is x $$\times$$ 10²⁰. The value of x is __________. [Given : h = 6.63 $$\times$$ 10^$$-$$34 Js and c = 3.0 $$\times$$ 10⁸ ms^$$-$$1]