The bond length of H${}_2^{+}$, H${}_2^{-}$ and H₂ are in the following order

• H${}_2^{+}$ > H₂ > H${}_2^{-}$

• H₂ > ${\text{H}}_2^{+} > {\mathrm{H}}_2^{-}$

• H${}_2^{-}$ > H₂ > H${}_2^{+}$

• ${\mathrm{H}}_2^{-} > {\mathrm{H}}_2^{+}$ > H₂

Which of the following is not a buffer ?

• NH₃ + HCl

• CH₃COOH + NaOH

• HCOOH + HCOOK

• NaOH + NaNO₃

At a certain temperature, the solubility of the salt, M_mA_n in water is s mol/L. The solubility product of the salt is

• M^mAⁿ

• (m + n)s^{m + n}

• m^mnⁿs^{m + n}

• m^mAⁿs

4.

The conjugated base of hydrazoic acid is

• HN${}_3^{-}$

• N${}_2^{-}$

• N${}_3^{-}$

• N^3-

The correct order of bond length is

• b > a > c > d

• a > b > c > d

• d > c > b > a

• c > d > b > a

Born-Haber cycle can be used to estimate

• electronegativity

• electron affinity

• ionic radii

• All of these

Consider the following ions:

(i) Ni²⁺   (ii) Co²⁺  (iii) Cr²⁺   (iv) Fe³⁺

(Given, at. no. Cr = 24, Fe = 26, Co = 27, Ni = 28)

The correct order of magnetic moment of these ions is

• (i) < (ii) < (iii) < (iv)

• (iv) < (ii) < (iii) < (i)

• (i) < (iii) < (ii) < (iv)

• (iii) < (iv) < (ii) < (i)

According to Bohr's theory, the angular momentum for an electron in 5^th orbit is

• 2.5 h/ $\mathrm{\pi }$

• 5 h/ $\mathrm{\pi }$

• 25 h/ $\mathrm{\pi }$

• 5 $\mathrm{\pi }$/ 2h

Which is heaviest ?

• 25g mercury

• 2 mol carbon dioxide

• 2 mol water

• 4 g-atom of oxygen

In stoichiometric defect, the ratio of positive and negative ions as indicated by chemical formula of the compound

• decreases

• increases

• changes by a factor of 2

• remains same