0.35 g of an organic substance was Kjeldahlised and the ammonia obtained was passed into 100 ml of N/5 H_(2)SO_(4). The excess acid required 154 ml of N/10 NaOH for neutralisation. Calculate the percentage of nitrogen in the compound.

0.35 g of an organic substance was Kjeldahlised and the ammonia obtain

1.	0.35 g of an organic substance was Kjeldahlised and the ammonia obtained was passed into 100 ml of N/5 H_(2)SO_(4). The excess acid required 154 ml of N/10 NaOH for neutralisation. Calculate the percentage of nitrogen in the compound.
Answer» Solution :Volume of `N//5 H_(2)SO_(4)` solution taken = 100 mL The volume of `N//5 H_(2)SO_(4)` neutralised by N/10 NAOH can be obtained as follows : `N_("acid")xxV_("acid")=N_("ALKALI")xxV_("alkali")` `(N)/(5)xx V_("acid")=(N)/(10)xx154mL` `V_("acid")=(154)/(10)xxmL` = 77 NL. Therefore, Volume of `N//% H_(2)SO_(4)` used for neutralisting ammonia `=(100-77)mL` `=23mL` Then, `"Percentage of nitrogen in the sample "="1.4"xx"Normality volume of acid"` `("used for neutralising "NH_(3))/("Mass of the compound taken")` Percentage of nitrogen in the sample `=(1.4xx1//5xx23)/(0.35)=18.4`