In the estimation of sulphur by carius method, 0.468g of an organic sulphur compound yeilded 0.668g of barium sulphate.Find the percentage of sulphur in the given compound.

0.05 g of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in 50 ml of 0.5 MH_2SO_4 . The residual acid required 60ml of 0.5 M solution of NaOH for neutralization. Find the percentage composition of nitrogen in the given compound.

A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144g of oxygen. Calculate the percentage composition of the compound by weight.

Write down the reaction involved in the detection of nitrogen and sulphur in an organic compound by Lassaigne's test.

A sample of concentrated sulphuric acid used in the laboratory is 98% by mass in aqueous solution. If the density of the solution is 1.835 g mL^-1 . Calculate the molarity of the sulphuric acid sample.

A solution is prepared by dissolving 1.25g of oil wintergreen (methyl salicylate) in 99.0g of benzene has or boiling point of 80.31^@C . Determine the molar mass of this compound. (bp of pure benzene, 80.10^@C and K_b for benzene, 2.53^@Ckg mol -1 )

An organic compound (A) on treatment with acetic acid in presence of sulphuric acid pro-duces as ester(B). (A) on mild oxidation gives (C). (C) with 50% KOH followed by acidifica-tion with dill HCI generates (A) and (D). (D) with PCI_5 followed by reaction with ammonia give (E). (E) on dehydration produces HCN-acid. Identify A to E.

Two elements A and B form compounds having formula AB_2 and AB_4 . When dissolved in 20 g of benzene (C_6H_6) , 1 g of AB_2 lowers the freezing point by 2.3 K whereas 1.0 g of AB_4 lowers it by 1.3 K. The molar depression constant for benzene is 5.1 K kg mol^-1 . Calculate atomic masses of A and B.

Calculate the mass of compound ( molar mass = 256 g mol^(-1) ) to be dissolved in 75 g of benzene to lower its freezing point by 0.48 K (Kf= 5.12 K kg mol^(-1)) .