Q 21 :

In Dumas method for estimation of nitrogen, 0.50 g of an organic compound gave 70 mL of nitrogen collected at 300 K and 715 mm pressure. The percentage of nitrogen in the organic compound is _____ %.

(Aqueous tension at 300 K is 15 mm.)                 [2026]

Q 22 :

Sodium fusion extract of an organic compound (Y) with ${\mathrm{CHCl}}_3$ and chlorine water gives violet color to the ${\mathrm{CHCl}}_3$ layer. 0.15 g of (Y) gave 0.12 g of the silver halide precipitate in Carius method. Percentage of halogen in the compound (Y) is __________. (Nearest integer)

(Given: molar mass g ${\mathrm{mol}}^{-1}$ C : 12, H : 1, Cl : 35.5, Br : 80, I : 127)                [2026]

Q 23 :

The cycloalkene (X) on bromination consumes one mole of bromine per mole of (X) and gives the product (Y) in which C : Br ratio is 3 : 1. The percentage of bromine in the product (Y) is __________ %. (Nearest integer)

(Given: molar mass in g ${\mathrm{mol}}^{-1}$ H : 1, C : 12, O : 16, Br : 80)              [2026]

Q 24 :

0.25 g of an organic compound "A" containing carbon, hydrogen and oxygen was analysed using the combustion method. There was an increase in mass of ${\mathrm{CaCl}}_2$ tube and potash tube at the end of the experiment. The amount was found to be 0.15 g and 0.1837 g, respectively. The percentage of oxygen in compound A is ______ %. (Nearest integer)

[Given: molar mass in g ${\mathrm{mol}}^{-1}$ H : 1, C : 12, O : 16]                   [2026]

Q 25 :

In Carius method 0.2425 g of an organic compound gave 0.5253 g silver chloride. The percentage of chlorine in the organic compound is  [2026]

• 34.79%

   

• 37.57%

   

• 87.65%

   

• 53.58%

   

Q 26 :

By usual analysis, 1.00 g of compound (X) gave 1.79 g of magnesium pyrophosphate. The percentage of phosphorus in compound (X) is : ______ (nearest integer)

(Given, molar mass in g ${mol}^{-1}$: O = 16, Mg = 24, P = 31)     [2026]

• 50

   

• 30

   

• 40

   

• 20

   

Q 27 :

When 1 g of compound (X) is subjected to Kjeldahl's method for estimation of nitrogen, 15 mL 1 M $H_{2}S{O}_4$ was neutralized by ammonia evolved. The percentage of nitrogen in compound (X) is :        [2026]

• 0.42

   

• 42

   

• 0.21

   

• 21

   

Q 28 :

Method used for separation of mixture of products (B and C) obtained in the following reaction is:    [2026]

• Simple distillation

   

• Fractional distillation

   

• Sublimation

   

• Steam distillation

   

Q 29 :

500 mL of 1.2 M KI solution is mixed with 500 mL of 0.2 M $KMn{O}_4$ solution in basic medium. The liberated iodine was titrated with standard 0.1 M $N{a}_2{S}_2{O}_3$solution in the presence of starch indicator till the blue color disappeared. The volume (in L) of $N{a}_2{S}_2{O}_3$ consumed is _____. (Nearest integer)            [2026]

Q 30 :

0.53 g of an organic compound (x) when heated with excess of nitric acid (concentrated) and then with silver nitrate gave 0.75 g of silver bromide precipitate. 1.0 g of (x) gave 1.32 g of $C{O}_2$ gas on combustion. The percentage of hydrogen in the compound (x) is ____%. [Nearest Integer]

[Given: Molar mass in g $mo{l}^{-1}$ H : 1, C : 12, Br : 80, Ag : 108, O : 16 ;
Compound (x) : $C_x{H}_{y}B{r}_z$]        [2026]