The correct order of magnitude of bond angles among the compounds CH₄, NH₃ and H₂O is

• CH₄ > H₂O < NH₃

• H₂O < NH₃ < CH₄

• NH₃ < CH₄ < H₂O

• NH₃ < H₂O < CH₄

The dissociation equilibrium of a gas AB₂ can be represented as

2AB₂ (g) $\rightleftharpoons$2AB (g) + B₂(g)

The degree of dissociation is 'x' and is small compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant KP and total pressure p is

• $\frac{2K_p}{p}$

• ${\left(\frac{2K_p}{p}\right)}^{\frac{1}{3}}$

• ${\left(\frac{2K_p}{p}\right)}^{\frac{1}{2}}$

• $\frac{K_p}{p}$

A buffer solution is prepared in which the concentration of NH₃ is 0.30 M and the concentration of N${\mathrm{H}}_4^{+}$ is 0.20 M. If the equilibrium constant, K_b for NH₃ equals 1. 8 x 10^-5, what is the pH of this solution? (log 2. 7 =0. 43).

• 9.43

• 11.72

• 8.73

• 9.08

If a gas expands at constant temperature indicates that

• kinetic energy of molecules decreases

• pressure of the gas increases

• kinetic energy of molecules remains as same

• number of the molecules of gas increase

If n = 6, the correct sequence for filling of electrons will be

• ns $\to$(n - 1)d $\to$(n - 2)f $\to$np

• ns $\to$(n - 2)f $\to$np $\to$(n - 1)d

• ns $\to$np $\to$(n - 1)d $\to$(n - 2)f

• ns $\to$(n - 2)f $\to$(n - 1)d $\to$np

Which of the following is least likely to behave as Lewis base?

• NH₃

• BF₃

• OH^-

• H₂O

For the reaction, N₂(g) + O₂(g) $\rightleftharpoons$ 2NO (g), the equilibrium constant is K₁. The equilibrium constant is K₂ for the reaction, 2NO(g) + O₂)g) $\rightleftharpoons$ 2NO₂(g). What is K for the reaction, NO₂(g) $\rightleftharpoons$$\frac{1}{2}{\mathrm{N}}_2 \left(\mathrm{g}\right) + {\mathrm{O}}_2\left(\mathrm{g}\right)$ ?

• $\frac{1}{4{\mathrm{K}}_1{\mathrm{K}}_2}$

• ${\left[\frac{1}{{\mathrm{K}}_1{\mathrm{K}}_2}\right]}^{\frac{1}{2}}$

• $\frac{1}{{\mathrm{K}}_1{\mathrm{K}}_2}$

• $\frac{1}{2{\mathrm{K}}_1{\mathrm{K}}_2}$

The angular shape of ozone molecule (O₃) consists of

• 1 sigma and 2 pi bonds

• 2 sigma and 2 pi bonds

• 1 sigma and 1 pi bonds

• 2 sigma and 1 pi bonds

Among the following the molecule possessing highest dipole moment is

• CO₂

• BF₃

• SO₂

• Trans-2-butene

10.

An electron is moving in Bohr's fourth orbit. Its de-Broglie wave length is $\mathrm{\lambda }$. What is the circumference of the fourth orbit?

• $\frac{2}{\mathrm{\lambda }}$

• 2$\mathrm{\lambda }$

• 4$\mathrm{\lambda }$ 

• $\frac{4}{\mathrm{\lambda }}$