Deep blue CusO₄·5H₂O is converted to a bluish white salt at 100°C. At 250°C and 750°C it is then transformed to a white powder and black material respectively. Identify the salts.

A 100 mL 0.1 = (M) solution of ammonium acetate is diluted by adding 100 mL of water. The pH of the resulting solution will be (pK_a of acetic acid is nearly equal to pK_b of NH₄OH).

• 4.9

• 5.0

• 7.0

• 10.0

In a reversible chemical reaction at equilibrium, if the concentration of any one of the reactants is doubled, then the equilibrium constant will

• also be doubled

• be halved

• remains the same

• becomes one-fourth

The pH of an aqueous solution of CH₃COONa of concentration C(M) is given by

• 7 - $\frac{1}{2}$pK_a - $\frac{1}{2}$log C

• $\frac{1}{2}$pK_w + $\frac{1}{2}$pK_b + $\frac{1}{2}$log C

• $\frac{1}{2}$pK_w - $\frac{1}{2}$pK_b - $\frac{1}{2}$log C

• $\frac{1}{2}$pK_w + $\frac{1}{2}$pK_a + $\frac{1}{2}$log C

If the equilibrium constants of the following equilibria,

SO₂ + $\frac{1}{2}$O₂ → SO₃ and 2SO₃ → 2SO₂ + O₂

are given by K₁ and K₂ respectively, which of the following realation is correct?

• K₂ = ${\left(\frac{1}{{\mathrm{K}}_1}\right)}^2$

• K₁ = ${\left(\frac{1}{{\mathrm{K}}_2}\right)}^3$

• K₂ = $\left(\frac{1}{{\mathrm{K}}_1}\right)$

• K₂ = (K₁)²

20 mL 0.1 (N) acetic acid is mixed with 10 mL 0.1(N) solution of NaOH. The pH of the resulting solution is (pK_a of acetic acid is 4.74)

• 3.74

• 4.74

• 5.74

• 6.74

Which of the following is used to prepare Cl₂ gas at room temperature from concentrated HCl?

• MnO₂

• H₂S

• KMnO₄

• Cr₂O₃

The solubility of Ca₃(PO₄)₂ in water is y mol/L. Its solubility product is

• 6y⁴

• 36y⁴

• 64y⁵

• 108y⁵

A compound on burning in air produces three oxides. Out of these one oxide turns lime water milky, the second one turned anhydrous CuSO₄ blue and third forms a solution of pH = 9. The compound is made up of

• S, N and H

• S, H and Na

• S and N

• S, C and H

What is the conjugate base of OH ?

• O₂

• H₂O

• O^-

• O^2-