Question

Answer the following questions for the reaction

NiCl2(aq)+2NaOH(aq)→Ni(OH)2(s)+2NaCl(aq)

A.How many milliliters of 0.200 M NaOH solution are needed to react with 42.0 mL of a 0.320 M NiCl2 solution?

Express your answer with the appropriate units.

B.How many grams of Ni(OH)2 are produced from the reaction of 51.0 mL of a 2.00 M NaOH solution and excess NiCl2?

Express your answer with the appropriate units.

C.What is the molarity of 30.0 mL of a NiCl2 solution that reacts completely with 17.7 mL of a 0.310 M NaOH solution?

Express your answer with the appropriate units.

Answer 1

A)

Use:

mol of NaOH = 2*number of mol of NiCl2

M(NaOH)*V(NaOH) = 2*M(NiCl2)*V(NiCl2)

0.200*V = 2*0.320*42.0

V = 134 mL

Answer: 134 mL

B)

mol of NaOH = M(NaOH)*V(NaOH)

= 2.00 M * 0.0510 L

= 0.102 mol

From reaction,

mol of Ni(OH)2 = (1/2)*mol of NaOH

= (1/2)*0.102 mol

= 0.051 mol

Molar mass of Ni(OH)2,

MM = 1*MM(Ni) + 2*MM(O) + 2*MM(H)

= 1*58.69 + 2*16.0 + 2*1.008

= 92.706 g/mol

use:

mass of Ni(OH)2,

m = number of mol * molar mass

= 5.1*10^-2 mol * 92.71 g/mol

= 4.728 g

Answer: 4.73 g

C)

Use:

mol of NaOH = 2*number of mol of NiCl2

M(NaOH)*V(NaOH) = 2*M(NiCl2)*V(NiCl2)

0.310*17.7 = 2*M*30.0

M = 0.0914 M

Answer: 0.0914 M