Some Basic Concepts of Chemistry

The mass of iron converted into Fe3O4 by the action of 18 g of steam is : (Given : Molar mass of H, O and Fe are 1, 16 and 56 g mol-1 respectively) Assume iron is present in excess :

1. 2.1 g
2. 4.2 g
3. 21 g
4. 42 g

The ratio of mass percentage (w/w) of C : H in a hydrocarbon is 12 : 1. It has two carbon atoms. The weight (in g) of CO2(g) formed when 3.38 g of this hydrocarbon is completely burnt in oxygen is : (Given : Molar mass in g mol-1 C : 12, H : 1, O : 16)

1. 5.68
2. 11.44
3. 22.74
4. 17.05

For the given reaction; CaCO3 + 2HCl CaCl2 + H2O + CO2 If 90 g CaCO3 is added to 300 mL of HCl which contains 38.55% HCl by mass and has density 1.13 g mL-1, then which of the following option is correct? Given molar mass of H, Cl, Ca and O are 1, 35.5, 40 and 16 g mol-1 respectively.

1. 64.97 g of HCl remains unreacted
2. 60.32 g of HCl remains unreacted
3. 32.85 g of CaCO3 remains unreacted
4. 97.30 g of HCl reacted

A student has planned to prepare acetanilide from aniline using acetic anhydride. The student has started from 9.3 g of aniline. However, the student has managed to obtain 11 g of dry acetanilide. The % yield of this reaction is :-

1. 59.5\%
2. 72.5\%
3. 97.5\%
4. 81.5\%

x mg of pure HCl was used to make an aqueous solution. 25.0 mL of 0.1 M Ba(OH)2 solution is used when the HCl solution was titrated against it. The numerical value of x is 10-1. (Nearest integer) Given : Molar mass of HCl and Ba(OH)2 are 36.5 and 171.0 g mol-1 respectively.

In the reaction, 2Al(s) + 6HCl(aq) 2Al3+(aq) + 6Cl-(aq) + 3H2(g)

1. 12 L HCl(aq) is consumed for every 6 L H2(g) produced.
2. 11.2 L H2(g) at STP is produced for every mole of HCl consumed.
3. 33.6 L H2(g) is produced regardless of temperature and pressure for every mole of Al that reacts.
4. 67.2 L H2(g) at STP is produced for every mole of Al that reacts.

At T(K), 100 g of 98\% H2SO4 (w/w) aqueous solution is mixed with 100 g of 49\% H2SO4 (w/w) aqueous solution. What is the mole fraction of H2SO4 in the resultant solution? (Given : Atomic mass H = 1 u; S = 32 u; O = 16 u). (Assume that temperature after mixing remains constant)

1. 0.9
2. 0.663
3. 0.1
4. 0.337

A + 2B AB2 36.0 g of 'A' (Molar mass : 60 g mol-1) and 56.0 g of 'B' (Molar mass : 80 g mol-1) are allowed to react. Which of the following statements are correct ? Choose the correct answer from the options given below :

1. A and C Only
2. A and B Only
3. C and D Only
4. B and D Only

14.0 g of calcium metal is allowed to react with excess HCl at 1.0 atm pressure and 273 K. Which of the following statements is incorrect? [Given : Molar mass in g mol-1 of Ca – 40, Cl – 35.5, H – 1]

1. The limiting reagent is calcium metal.
2. 33.3 g of CaCl2 is produced.
3. 7.84 L of H2 gas is evolved.
4. 0.35 mol of H2 gas is evolved.

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is :

1. C2H2
2. C2H4
3. C4H10
4. C2H6