The electronegativity of halogen is as :

F > Cl >  Br > I

Among alkali metals the electropositive character increases as :

Li < Na < K < Rb < Cs

Hence, LiF is the most stable compound.

The ratio of O₂ and N₂ by weight is 1: 4

Therefore, the ratio of O₂ and N₂ by moles =

$\frac{1}{32} : \frac{4}{28}$ = 7 : 32

Hence, the ratio of the number of molecules is 7 : 32.

When copper reacts with hot and conc. H₂SO₄, SO₂ is produced.

Cu + 2H₂SO₄ $\to$ CuSO₄ + SO₂ + 4H₂O

Entropy change of fusion

$∆{\mathrm{S}}_{\mathrm{f}} = \frac{∆{\mathrm{H}}_{\mathrm{f}}}{\mathrm{T}}$

$∆{\mathrm{H}}_{\mathrm{f}}$= 60 x 10³ JK mol^-1; T = 273 K

$$\begin{gathered} ∆{\mathrm{S}}_{\mathrm{f}} = \frac{60 \times {10}^3}{273} \\ = 21.97 {\mathrm{JK}}^{-1 }{\mathrm{mol}}^{-1} \end{gathered}$$

According to Heisenberg uncertainty principle, the product of uncertainty in momentum ($∆$P) and in position ($∆$x) remains constant. Therefore, it can be explained using the following formula 

$∆\mathrm{x} \times ∆\mathrm{P} \ge \frac{\mathrm{h}}{4\mathrm{\pi }}$

X in the following reaction is gamma.

₇N¹⁴ + ₁H¹ $\to$ ₈O¹⁵ + $\mathrm{\gamma }$

Neutrons are the particles in an atom that have a neutral charge. These particles were discovered by Chadwick.

BaO₂ and ozone reacts to produce BaO and oxygen.

BaO₂ + O₃ $\to$ BaO + 2O₂

Here, V₁ = 10 L; V₂ = 2 L

p₁ = 1 atm; p₂ = 1 atm

T₁ = 300 K; T₂ = x

$$\begin{gathered} \frac{{\mathrm{p}}_1{\mathrm{V}}_1}{{\mathrm{T}}_1} = \frac{{\mathrm{p}}_2{\mathrm{V}}_2}{{\mathrm{T}}_2} \\ \frac{1 \times 10}{300 } = \frac{1 \times 2}{{\mathrm{T}}_2} \\ {\mathrm{T}}_2 = \frac{300 \times 2}{10} = 60 \mathrm{K} \end{gathered}$$

The de broglie wavelength of a particle with mass 1 kg and velocity 100 m/s is 6.6 x 10^-36 m.

$\mathrm{\lambda } = \frac{\mathrm{h}}{\mathrm{mv}}$ = $\frac{6.6 \times {10}^{-34}}{1 \times 100}$

  = 6.6 x 10^-36 m