Some Basic Concepts of Chemistry

An oxide of iron contains 69.9% iron, its empirical formula, is: (Given : Molar mass of Fe and O are 56 and 16 g mol-1 respectively.)

1. FeO
2. Fe2O3
3. Fe3O4
4. FeO3

Which of the following contain the same number of atoms? (Given : Molar mass in g mol-1 of H, He, O and S are 1, 4, 16 and 32 respectively) Choose the correct answer from the options given below :

1. A and B only
2. B and C only
3. C and D only
4. A, C and E only

How many grams of residue is obtained by heating 2.76 g of silver carbonate? (Given : Molar mass of C, O and Ag are 12, 16 and 108 g mol-1 respectively)

1. 1.08 g
2. 2.16 g
3. 3.24 g
4. 4.32 g

What volume of hydrogen gas at STP would be liberated by action of 50 mL of H2SO4 of 50% purity (density = 1.3 g mL-1) on 20 g of zinc? Given : Molar mass of H, O, S, Zn are 1, 16, 32, 65 g mol-1 respectively.

1. 5.824 L
2. 7.428 L
3. 6.892 L
4. 8.375 L

Number of moles and number of molecules in 1.4187 L of SO2 at STP respectively are

1. 0.1266; 3.812 1022
2. 0.0633; 3.812 1022
3. 0.1266; 7.6238 1022
4. 0.0633; 7.6238 1022

The correct order of total number of atoms present in (A) 2 moles of cyclohexane (B) 684 g of sucrose (C) 90.8 L of dihydrogen at STP is :

1. C > A > B
2. C > B > A
3. B > C > A
4. B > A > C

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\%

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

Aqueous HCl reacts with MnO2(s) to form MnCl2(aq), Cl2(g), and H2O(l). What is the weight (in g) of Cl2 liberated when 8.7 g of MnO2(s) is reacted with excess aqueous HCl solution? (Given Molar mass in g mol-1 Mn = 55, Cl = 35.5, O = 16, H = 1)

1. 14.2
2. 21.3
3. 7.1
4. 71

Among 10-9 g (each) of the following elements, which one will have the highest number of atoms? Element: Pb, Po, Pr and Pt

1. Pr
2. Pt
3. Po
4. Pb

Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is Given: Molar mass of Mg is 24 g mol-1.

1. 0.24 mg
2. 235.7 g
3. 2.444 g
4. 236 mg

10 mL of 2 M NaOH solution is added to 20 mL of 1 M HCl solution kept in a beaker. Now, 10 mL of this mixture is poured into a volumetric flask of 100 mL containing 2 moles of HCl and made the volume up to the mark with distilled water. The solution in this flask is :

1. 0.2 M NaCl solution
2. 20 M HCl solution
3. Neutral solution
4. 10 M HCl solution

CaCO3(s)+2HCl(aq) CaCl2(aq)+CO2(g)+H2O(l) Consider the above reaction, what mass of CaCl2 will be formed if 250 mL of 0.76 M HCl reacts with 1000 g of CaCO3 ? (Given : Molar mass of Ca, C, O, H and Cl are 40, 12, 16, 1 and 35.5 g mol-1, respectively)

1. 3.908 g
2. 2.636 g
3. 10.545 g
4. 5.272 g

On complete combustion 1.0 g of an organic compound (X) gave 1.46 g of CO2 and 0.567 g of H2O. The empirical formula mass of compound (X) is g. (Given molar mass in g mol-1 C : 12, H : 1, O : 16)

1. 60
2. 45
3. 30
4. 15

'x' g of NaCl is added to water in a beaker with a lid. The temperature of the system is raised from 1 C to 25 C. Which out of the following plots, is best suited for the change in the molarity (M) of the solution with respect to temperature? [Consider the solubility of NaCl remains unchanged over the temperature range]

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Choose the correct statements. Choose the correct answer from the options given below :

1. (B), (C) and (D) Only
2. (A), (B) and (C) Only
3. (C), (D) and (E) Only
4. (A), (D) and (E) Only

0.1 M solution of KI reacts with excess of H2SO4 and KIO3 solutions. According to equation 5I- + IO3- + 6H+ 3I2 + 3H2O Identify the correct statements : Choose the correct answer from the options given below :

1. (C) and (D) only
2. (A) and (B) only
3. (B) and (C) only
4. (A) and (D) only

Concentrated nitric acid is labelled as 75% by mass. The volume in mL of the solution which contains 30 g of nitric acid is . Given : Density of nitric acid solution is 1.25 g/mL.

1. 32
2. 40
3. 55
4. 45

The elemental composition of a compound is 54.2\% C, 9.2\% H and 36.6\% O. If the molar mass of the compound is 132 g mol-1, the molecular formula of the compound is : [Given : The relative atomic mass of C:H:O=12:1:16]

1. C4H8O2
2. C6H12O6
3. C4H9O3
4. C6H12O3

What amount of bromine will be required to convert 2 g of phenol into 2,4,6-tribromophenol? (Given molar mass in g mol-1 of C, H, O, Br are 12, 1, 16, 80 respectively )

1. 6.0 g
2. 10.22 g
3. 20.44 g
4. 4.0 g

2.8 10-3 mol of CO2 is left after removing 1021 molecules from its ' x ' mg sample. The mass of CO2 taken initially is Given: NA = 6.02 1023 mol-1

1. 98.3 mg
2. 196.2 mg
3. 150.4 mg
4. 48.2 mg

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 'A' 1012 hertz and that has a radiant intensity in that direction of 1'B' watt per steradian. 'A' and 'B' are respectively

1. 450 and 683
2. 540 and 1683
3. 540 and 683
4. 450 and 1683

Combustion of glucose ( C6H12O6) produces CO2 and water. The amount of oxygen (in g) required for the complete combustion of 900 g of glucose is : [Molar mass of glucose in g mol-1 = 180]

1. 32
2. 480
3. 800
4. 960