I only want the answers no need for explanation 1 Which one

I only want the answers, no need for explanation.

1. Which one of the following is NOT a buffer solution?

A.     NH₃ and NH₄Cl

B.     CH₃COOH and CH₃COONa

C.     NaHCO₃ and Na₂CO₃

D.     HClO₄ and NaClO₄

2. When a 25-mL sample of Ba(OH)₂ is titrated to the equivalence point with 35.8 mL of 0.150 M HCl, what was the concentration of the original Ba(OH)₂?

A.     0.105 M

B.     0.215 M

C.     0.107 M

D.     0.430 M

3. Consider a buffer solution prepared from HCN and NaCN. Which reaction shows how the buffer minimizes pH changes when NaOH is added?

A.     OH^- + CN^- ® HCNO

B.     H⁺ + CN^- ® HCN

C.     OH^- + H⁺ ® H₂O

D.     OH^- + HCN ® H₂O + CN^-

4. On the basis of the information below, a buffer with a pH = 2 can best be made by using

A.     only H₃PO₄.

B.     H₃PO₄ and KH₂PO₄.

C.     KH₂PO₄ and K₂HPO₄.

D.     K₂HPO₄ and K₃PO₄.

5. The addition of solid NaOH to a saturated aqueous solution of Cu(OH)₂ will cause

A.     precipitation of more Cu(OH)₂

B.      more Cu(OH)₂ to dissolve

C.      no change of the Cu²⁺ concentration in solution

D.     the Ksp of Cu(OH)₂ to decrease

A.     only H3PO4. B.     H3PO4 and KH2PO4. C.     KH2PO4 and K2HPO4. D.     K2HPO4 and K3PO4.

THPO4.7*10-).[HPO, ...8*10-ºj...[HPO ........5*10-131

Solution

Ans. #1. Correct option- D. HClO₄ and NaClO₄

A solution of strong acid and its salt does not act as a buffer.

#2. At equivalence point, the total number of moles of H⁺ from acid is equal to total number of OH^- from base.

That is-           x(M1V1), acid = y(M2V2), base

            Where, x = moles of H⁺ produced per mol acid = 1 for HCl

                        y = moles of OH^- produced per mol base = 2 for Ba(OH)₂

                        V and M are volume and molarity of respective solution.

Putting the values in above expression-

                        1 (0.150 x 35.8 mL) = 2 x (M2 x 25.00 mL)

                        Or, M2 = (0.150 M x 35.8 mL) / (2 x 25.0 mL)

                        Hence, M1 = 0.1074 M

Therefore, molarity of Ba(OH)₂ = 0.1074 M

So, correct option is- C. 0.107 M

#3. Correct option- B. H⁺ + CN^- <-----> HCN

Either the weak acid (HCN) shall donate its proton

Or,

The conjugate base (CN^-) shall accept a proton.

#4. Correct option- B. The weak acid H₃PO₄ and its salt KH₂PO₄.

The weak acid with its pKa closest to desired buffer pH is preferred. A weak acid and its salt forms the buffer.

#5. Correct option- A. Precipitation od more Cu(OH)₂