The function of boiling the sodium extract with conc. HNO3 before testing for halogen is:


Correct option is

If N and S are already present, they will hinder in test of halogens as NaCNand Na2S will give white or black precipitate with AgNO3. Boiling conc. HNO3 is thus used to remove CN and S2– ions in the form of volatile HCN and H2S.



0.156 g of an organic compound on heating with fuming HNO3 and AgNO3 gives 0.235 g of AgI. Calculate the percentage of the iodine in the compound.


276 g of silver carbonate on being strongly heated yields a residue weighing


An organic compound on analysis gave the data : 0.25 g of the compound on complete combustion gave 0.37 g of CO2 and 0.2 g of water.


0.2 g of an organic compound was analysed by Kjeldahl’s method. Ammonia evolved was absorbed in 60 ml N/5 H2SO4. Unused acid required 40 ml of N/10 NaOH for complete neutralisation. Find the percentage of nitrogen in the compound.


1.216 g of an organic compound was reacted under Kjeldahl’s method and ammonia evolved was absorbed in 100 ml N H2SO4. The remaining acid solution was made up to 500 ml by addition of water 20 ml of this dilute solution required 32 ml of N/10 caustic soda solution for complete neutralisation. Calculate the percentage of nitrogen in the compound. 


0.5264 g silver bromide is obtained from 0.5124 g of an organic compound. Calculate the percentage of bromine in the compound.


0.1170 g of an organic compound on heating with conc. HNO3 and silver nitrate in Carius furnace gave 0.42 g of AgCl. Find the percentage of chlorine in the compound.


On heating 0.32 g of an organic compound with concentrated nitric acid and barium chloride, 0.932 g barium sulphate was obtained. Calculate the percentage of sulphur in the given compound.


6 g of an organic compound containing oxygen is heated with graphite and carbon monoxide formed is quantitatively converted to 8.8 g CO2 on reaction with I2O5. Calculate percentage of oxygen in the compound.



For the reaction,


5 moles of X and 9 moles of Y will produce