A solution containing Na_(2)CO_(3) and NaOH requires 300 mL of 0.1 N HCl using phenolphthalein as an indicator. Methyl orange is then added to above titrated solution when a further 25 mL of 0.2 N HCl is required. The amount of NaOH present in the original solution is :

A solution containing Na_(2)CO_(3) and NaOH requires 300 mL of 0.1 N H

1.	A solution containing Na_(2)CO_(3) and NaOH requires 300 mL of 0.1 N HCl using phenolphthalein as an indicator. Methyl orange is then added to above titrated solution when a further 25 mL of 0.2 N HCl is required. The amount of NaOH present in the original solution is :
Answer» 0.5 g 1 g 2 g 4 g Solution :300 mL HCl of 0.1 N NEUTRALISES entire amount of NaOH and `1//2 " of" Na_(2)CO_(3)`. Remaining `1//2 " of " Na_(2)CO_(3)` is neutralised by 25 mL 0.2 N HCl, i.e., 50 mL of 0.1 N HCl. THUS, 250 mL of 0.1 N HCl is required to neutralise NaOH completely. `N_(1)V_(1)(NaOH)=N_(2)V_(2)(HCl)` `=0.1xx250` =25 `W_(NaOH)=(ENV)/(1000)=(40xx25)/(1000)=1 g`