Page 45 - Chemistry - XI

Observation Table

Burette readings ________ mL
S. No. Initial reading of Final reading Volume of oxalic acid used Volume of NaOH
burette of burette (V ) in mL uses in mL
1
1.
2.
3.

Volume of NaOH used (V ) = ________ mL
2
Calculations
M V = M V , M = Molarity of acid, M = Molarity of base
1 1 2 2 1 2
V = Volume of acid in mL, V = Volume of base in mL
1 2
0.1 × V =M × 25, suppose 23 mL of oxalic acid solution is used then
1 2
0.1 × 23 = M × 25 or M = 0.092 mole/litre
2 2
Strength of NaOH solution = M × Molecular weight
2
= 0.092 × 40 (M. wt. of NaOH)

= 3.68 g per litre
Result
The strength of given NaOH solution is ________ gL –1.

EXPERIMENT - 17

Objective
To prepare a standard solution of sodium carbonate (M/20).

Materials Required

Burette (50 mL), pipette (25 mL), conical fl ask (250 mL), burette stand, funnel, white glazed tile, measuring
fl ask, and Na CO .
3
2
Procedure
1. We will prepare 250 mL of M/20 sodium carbonate solution.

2. Amount of Na CO required to prepare M/20 solution in 250 mL 106 250 1 325. g
2 3
20 1000
3. Dissolve 1.325 g of Na CO in distilled water and prepare the standard solution in 250 mL of measuring
2
3
fl ask by adding required amount of water.
4. Thus prepared standard solution of sodium carbonate has molarity M/20 or 0.05 M.

43