Brass is an alloy of Cu-Zn. A sample of brass weighing 5.793 g, when treated with excess of dil. `H_2SO_4` gives 324 mi of dry `H_2` at `20^@C` and 750 mm pressure. What is the percentage of Cu by mass in the alloy ?

2g of mixture of CaCO_(3) and MgCO_(3) on being treated with dilute HCl gives 536.84 mL of CO_(2) at 27^(@)C and 750 mm of Hg pressure. What is the composition of the mixture?

Calculate the amount of copper which on reaction with conc. H_(2)SO_(4) produces 50 ml of SO_(2) at 27^(@)C and 750 mm pressure. (Cu=63.5)

2.5 g of an inpure sample of sodium bicarbonate when strongly heated gave 300ml of carbondioxide measured at 27^(@) and 760 mm pressure. Calculate the percentage purity of the sample. (Na=23, C=12, O=16).

When 0.3 g of a metal is dissolved in dilute HCl the volume of H_(2) gas liberated is 110 mL at 17^(@)C and 755 mm Hg of pressure. [Aqueous tension at 17^(@)C=14.4 mm Hg] Determine the equivalent mass of the metal.

An organic compound 'A' (C_2H_6O) reacts with sodium to form a compound 'B' with the evolution of hydrogen gas and gives a yellow compound 'C' when treated with iodine and NaOH. When heated with conc. H_2SO_4 at 140^@C it gives a compound 'D' C_4H_(10) which on treatment with HI at 100^@C gives 'E'. 'B' when heated with 'E' also gives back 'D'. Identify 'A' to 'E' and write equations for the reaction involved.

H_(2) gas liberated in the reaction of 13g of zinc with dilute H_(2)SO_(4) is separately passed over (i) 10 g and (ii) 20 g of dry cupric oxide. What is the amount of the residue remain in each case?