Question

66. A student needs 500 ml of SOM HC solution. How much in ml, of concentrated HCl is required to prepare this solution Concentrated 12.OM 67. A student weighs out 1.221 KHP and titrates to the equivalence point with 80. OmL of a standard NaOH solution. What is the concentration of the NaOH used to titrate the KHP? The molar mass of KHP is 204.22/mol 68. Hydrochloric Acid (HCI) is titrated with Sodium Hydroxide. Write and balance the chemical equation. 69. Barium Hydroxide is used to titrate a phosphoric acid (H3PO4) solution. Write and balance the chemical equation. bh 70. What type of reaction is given in the previous two questions?

Answer 1

66) Using M1V1(conc. HCl) = M2V2 (HCl solution)

12.0×V1 = 0.50×500

V1 = 250/12

= 20.83 ml

67) At equivalence point,

Moles of NaOH = moles of KHP = mass of KHP/molar mass

= 1.221/204.22 = 0.00598 moles

Concentration of NaOH = moles×1000/volume

= 0.00598×1000/80

= 0.0747 M

68) HCl(aq) + NaOH (aq) $\rightarrow$ NaCl(aq) + H2O (l)

69) Ba(OH)2(aq) + H3PO4 (aq) $\rightarrow$ Ba3(PO4)2(s) + H2O(l)

Balanced equation :

3Ba(OH)2(aq) + 2H3PO4(aq) $\rightarrow$ Ba3(PO4)2(s) + 6H2O(l)