The reactant which is entirely consumed in reaction is known as limiting reagent. In the reaction 2 A + 4 B → 3 C + 4 D . when 5 moles of A react with 6 moles of B, then (i) which is the limiting reagent? (ii) calculate the amount of C formed.

The given reaction is 2 A 2 mol + 4 B 4 mol → 3 C 3 mol + 4 D 4 mol Given moles for A and B are 5 and 6 moles respectively Case I. Let reactant A is completely consumed 2 mol A gives 3 mol C 5 mol A will give 3 2 × 5 mol C = 7 . 5 mol C Case II. Let reactant B is completely consumed 4 mol B gives 3 mol C 6 mol B will give 3 4 × 6 mol C = 4 . 5 mol C Since B on complete consumption gives lesser amount of product C. Hence, B will be limiting reagent and the amount of C formed will be 4 . 5 mol .

Match the following: Column I Column II (i) 88 g of CO 2 (a) 0 . 25 mol (ii) 6 . 022 × 10 23 molecules of H 2 O (b) 2 mol (iii) 5 . 6 litres of O 2 at STP (c) 1 mol (iv) 96 g of O 2 (d) 6 . 022 × 10 23 molecules (v) 1 mol of any gas (e) 3 mol

For CO 2 gas, molecular mass is 44 g . 44 g of carbon dioxide contains one mole, so that 88 g of carbon dioxide contains two moles. One mole of any substance contains Avogadro number of particles. One mole of water contains 6 . 022 × 10 23 molecules . 32 g of oxygen is equal to one mole so that 96 g of oxygen is equal to three moles. One mole of gas occupies 22 . 4 litres of volume. 5 . 6 litres of gas contains 0 . 25 mol. Column I Column II (i) 88 g of CO 2 (b) 2 mol (ii) 6 . 022 × 10 23 molecules of H 2 O (c) 1 mol (iii) 5 . 6 litres of O 2 at STP (a) 0 . 25 mol (iv) 96 g of O 2 (e) 3 mol (v) 1 mol of any gas (d) 6 . 022 × 10 23 molecules

Physical quantity Unit (i) Molarity (a) gmL - 1 (ii) Mole fraction (b) mol (iii) Mole (c) Pascal (iv) Molality (d) Unitless (v) Pressure (e) mol L - 1 (vi) Luminous intensity (f) Candela (vii) Density (g) mol kg - 1 (viii) Mass (h) Nm - 1 (i) kg

Number of moles of solute dissolved in one litre of solution is called molarity. Units of molarity is mol lit - 1 . The ratio between the number of moles of one component to the number of moles of all the components in a solution is called mole fraction. It does not have units. A mole corresponds to the mass of a substance that contains 6 . 023 × 10 23 particles of the substance. Unit of mole is mol. The number of moles of solute present in one kilogram of solvent is called molality. Units of molality is mol Kg - 1 . Pressure is defined to be the amount of force exerted per area. Units of pressure is bar , Pascal and atm . The luminous intensity is defined as the luminous flux per unit solid angle. The SI units of the luminous intensity are the candela. Density is the mass of a unit volume of a material substance. Units of density is g ml - 1 . Mass is a measure of the amount of matter in a substance or an object. The basic SI unit for mass is the kilogram ( Kg ). Physical quantity Unit (i) Molarity (e) mol L - 1 (ii) Mole fraction (d) Unitless (iii) Mole (b) mol (iv) Molality (g) mol kg - 1 (v) Pressure (c) Pascal (vi) Luminous intensity (f) Candela (vii) Density (a) g mL - 1 (viii) Mass (i) kg

EASY

11th CBSE

IMPORTANT

Earn 100

Volume of a solution changes with change in temperature, then, will the molality of the solution, be affected by temperature? Give reason for your answer.

Important Questions on Some Basic Concepts of Chemistry

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 34

4 g

NaOH

dissolves in

36 g

H_{2} O

, calculate the mole fraction of each component in the solution. Also, determine the molarity of solution (specific gravity of solution is

1 g {mL}^{- 1}

HARD

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 35

The reactant which is entirely consumed in reaction is known as limiting reagent. In the reaction $2 A + 4 B \to 3 C + 4 D$ . when $5$ moles of A react with $6$ moles of B, then

(i) which is the limiting reagent?

(ii) calculate the amount of C formed.

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Matching Type>Q 36

Match the following:

	Column I		Column II
(i)	$88 g of {CO}_{2}$	(a)	$0.25 mol$
(ii)	$6.022 \times 10^{23} molecules of H_{2} O$	(b)	$2 mol$
(iii)	$5.6 litres of O_{2} at STP$	(c)	$1 mol$
(iv)	$96 g of O_{2}$	(d)	$6.022 \times 10^{23} molecules$
(v)	$1 mol$ of any gas	(e)	$3 mol$

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Matching Type>Q 37

	Physical quantity		Unit
(i)	Molarity	(a)	${gmL}^{- 1}$
(ii)	Mole fraction	(b)	mol
(iii)	Mole	(c)	Pascal
(iv)	Molality	(d)	Unitless
(v)	Pressure	(e)	mol $L^{- 1}$
(vi)	Luminous intensity	(f)	Candela
(vii)	Density	(g)	mol ${kg}^{- 1}$
(viii)	Mass	(h)	${Nm}^{- 1}$
		(i)	kg

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Long Answer Type>Q 42

A vessel contains

1.6 g

of dioxygen at STP (

273.15 K, 1

atm

pressure). The gas is now transferred to another vessel at a constant temperature, where pressure becomes half of the original pressure. Calculate the volume of the new vessel.

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Long Answer Type>Q 42

A vessel contains

1.6 g

of dioxygen at STP (

273.15 K, 1

atm pressure). The gas is now transferred to another vessel at a constant temperature, where pressure becomes half of the original pressure. Calculate the number of molecules of dioxygen.

HARD

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Long Answer Type>Q 43

Calcium carbonate reacts with aqueous $HCl$ to give ${CaCl}_{2}$ and ${CO}_{2}$ according to the reaction given below:

${CaCO}_{3} (s) + 2 HCl (aq) \to {CaCl}_{2} (aq) + {CO}_{2} (g) + H_{2} O (l)$

What mass of ${CaCl}_{2}$ will be formed when $250 mL$ of $0.76 M HCl$ reacts with $1000 g$ of ${CaCO}_{3}$ ? Name the limiting reagent. Calculate the number of moles of ${CaCl}_{2}$ formed in the reaction.

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Long Answer Type>Q 44

Define the law of multiple proportions. Explain it with two examples. How does this law point to the existence of atoms?

Volume of a solution changes with change in temperature, then, will the molality of the solution, be affected by temperature? Give reason for your answer.

Important Questions on Some Basic Concepts of Chemistry

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