641.

For a phase change

${\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)} \underset{0^{°}\mathrm{C}, 1 \mathrm{bar}}{\rightleftharpoons } {\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{s}\right)}$

• $∆\mathrm{G} = 0$

• $∆\mathrm{H} = 0$

• $∆\mathrm{S} =0$

• $∆\mathrm{U} = 0$

F₂ formed by reacting K₂MnF₆ with

• SbF₅

• MnF₃

• KSbF₆

• MnF₄

Which among the following is the strongest acid ?

• HF

• HCl

• HBr

• HI

When 10 mL of 0.1 M acetic acid (pK_a = 5.0) is titrated against 10 ml of 0.1 M ammonia solution (pK_b = 5.0), the equivalence point occurs at pH

• 5.0

• 6.0

• 7.0

• 9.0

For reaction, 2NOCl _(g) $\rightleftharpoons$2NO _(g) + Cl_2 (g), K_c at 427°C is 3 × 10^-6 L mol^-1. The value of K_p is nearly

• 7.50 × 10^-5

• 2.50 × 10^-5

• 2.50 × 10^-4

• 1.75 × 10^-4

For the chemical equilibrium,

CaCO_3(s) $\rightleftharpoons$CaO_(s) + CO_2(g)

$∆{\mathrm{H}}_{\mathrm{r}}^{°}$ can be determined from which one of the following plots?

pH of a solution of 10 mL 1N sodium acetate and 50 mL 2N acetic acid (K_a = 1.8 x 10^-5), is approximately :

• 4

• 5

• 6

• 7

The pH is less than 7, of the solution of :

• FeCl₃

• NaCN

• NaOH

• NaCl

Dimethyl glyoxime gives a red precipitate with Ni²⁺, which is used for its detection. To get this precipitate readily the best pH range is

• < 1

• 2-3

• 3- 4

• 9- 11

The values of K_sp for CuS, Ag₂S and HgS are 10^-31, 10⁴², 10^-54 respectively. The correct order of their solubility in water is :

• AgS > HgS > CuS

• HgS > Cus > Ag₂S

• HgS > Ag₂S > Cus

• Ag₂S > CuS > HgS