Question

In this procedure it is important to store the sodium hydroxide, NaOH, solution securely capped to avoid evaporation of water. 1. What would the impact of leaving the plastic bottle of sodium hydroxide open to the atmosphere and allowing some of the water to evaporate be on the concentration of the solution. Would the concentration be higher, lower, or unchanged. Provide an explanation for your answer. 2. If the sodium hydroxide, NaOH, solution was not re-standardized after some of the water evaporated, what impact would this have on the quantity of sodium hydroxide solution needed to reach the endpoint for a given mass of acid? Would the quantity be higher, lower, or unchanged. Provide an explanation for your answer. If the sodium hydroxide, NaOH, solution was not re-standardized after some of the water evaporated, what impact would this have on the value of the acid molar mass calculated? Wold the value be higher, lower, or unchanged. Provide an explanation for your answer.

Answer 1

sodium hydroxide is hygroscopic in nature so when expose to air it react with carbondioxide present in the air to form sodium carbonate ,as a result of this the strength of it decrease and it need to be standardised

2 as the concentration decrease so we need more quantity of sodium hydroxide  

3 the mass of acid comes out to be less than the true value. as the strength of sodium hydroxide decrease so accordingly calculated mass comes less