Some Basic Concepts of Chemistry

'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

The molarity of a 70\% (mass/mass) aqueous solution of a monobasic acid (X) is 10-1 M (Nearest integer) [Given: Density of aqueous solution of (X) is 1.25 g mL-1 Molar mass of the acid is 70 g mol-1]

Quantitative analysis of an organic compound (X) shows following % composition. C : 14.5\% Cl : 64.46\% H : 1.8\% Empirical formula mass of the compound (X) is 10-1 (Given molar mass in g mol-1 of C : 12, H : 1, O : 16, Cl : 35.5)

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

Consider the following reaction occurring in the blast furnace: Fe3O4(s) + 4CO(g) 3Fe(l) + 4CO2(g) 'x' kg of iron is produced when 2.32 103 kg Fe3O4 and 2.8 102 kg CO are brought together in the furnace. The value of 'x' is . (nearest integer) Given: molar mass of Fe3O4 = 232 g mol-1 molar mass of CO = 28 g mol-1 molar mass of Fe = 56 g mol-1

Xg of benzoic acid on reaction with aq NaHCO3 released CO2 that occupied 11.2 L volume at STP. X is g.

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

0.01 mole of an organic compound (X) containing 10\% hydrogen, on complete combustion produced 0.9 g H2O. Molar mass of (X) is g mol-1.

When 81.0 g of aluminium is allowed to react with 128.0 g of oxygen gas, the mass of aluminium oxide produced in grams is . (Nearest integer) Given : Molar mass of Al is 27.0 g mol-1 Molar mass of O is 16.0 g mol-1

Some CO2 gas was kept in a sealed container at a pressure of 1 atm and at 273 K. This entire amount of CO2 gas was later passed through an aqueous solution of Ca(OH)2. The excess unreacted Ca(OH)2 was later neutralized with 0.1 M of 40 mL HCl. If the volume of the sealed container of CO2 was x, then x is cm3 (nearest integer). [Given : The entire amount of CO2(g) reacted with exactly half the initial amount of Ca(OH)2 present in the aqueous solution.]

20 mL of 2 M NaOH solution is added to 400 mL of 0.5 M NaOH solution. The final concentration of the solution is 10-2 M. (Nearest integer)

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

The density of 'x' M solution ('x' molar) of NaOH is 1.12 g mL-1, while in molality, the concentration of the solution is 3 m ( 3 molal). Then x is (Given : Molar mass of NaOH is 40 g/mol)

1. 3.8
2. 3.0
3. 3.5
4. 2.8

Molality (m) of 3M aqueous solution of NaCl is : (Given : Density of solution = 1.25 g mL-1, Molar mass in g mol-1 : Na - 23, Cl - 35.5)

1. 2.90 m
2. 3.85 m
3. 1.90 m
4. 2.79 m

The incorrect postulates of the Dalton's atomic theory are : Choose the correct answer from the options given below :

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

An organic compound has 42.1\% carbon, 6.4\% hydrogen and the remainder is oxygen. If its molecular weight is 342, then its molecular formula is :

1. C14H20O10
2. C12H22O11
3. C12H20O12
4. C11H18O12

The number of moles of methane required to produce 11 g CO2(g) after complete combustion is : (Given molar mass of methane in g mol-1 : 16)

1. 0.35
2. 0.25
3. 0.5
4. 0.75

The Molarity (M) of an aqueous solution containing 5.85 g of NaCl in 500 mL water is : (Given : Molar Mass Na : 23 and Cl : 35.5 g mol-1)

1. 20
2. 4
3. 2
4. 0.2

Choose the Incorrect Statement about Dalton's Atomic Theory

1. Compounds are formed when atoms of different elements combine in any ratio.
2. Matter consists of indivisible atoms.
3. Chemical reactions involve reorganization of atoms
4. All the atoms of a given element have identical properties including identical mass.

Consider the following reaction : 3PbCl2 + 2(NH4)3PO4 Pb3(PO4)2 + 6NH4Cl If 72 mmol of PbCl2 is mixed with 50 mmol of (NH4)3PO4, then the amount of Pb3(PO4)2 formed is mmol (nearest integer).

10 mL of gaseous hydrocarbon on combustion gives 40 mL of CO2(g) and 50 mL of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is .

Number of moles of methane required to produce 22 g CO2(g) after combustion is x 10-2 moles. The value of x is .

A sample of CaCO3 and MgCO3 weighed 2.21 g is ignited to constant weight of 1.152 g. The composition of mixture is : (Given molar mass in g mol-1 CaCO3 : 100, MgCO3 : 84)

1. 1.187 g CaCO3 + 1.187 g MgCO3
2. 1.187 g CaCO3 + 1.023 g MgCO3
3. 1.023 g CaCO3 + 1.187 g MgCO3
4. 1.023 g CaCO3 + 1.023 g MgCO3

The molarity of 1 L orthophosphoric acid (H3PO4) having 70% purity by weight (specific gravity 1.54 g cm-3) is M. (Molar mass of H3PO4 = 98 g mol-1)

The mass of sodium acetate (CH3COONa) required to prepare 250 mL of 0.35 M aqueous solution is g. (Molar mass of CH3COONa is 82.02 g mol-1)