In the reaction, 4 NH 3 g + 5 O 2 g → 4 NO g + 6 H 2 O l , when 1 mole of ammonia and 1 mole of O 2 are made to react to completion

all the oxygen will be consumed

1 . 0 mole of H 2 O is produced

1 . 0 mole of NO will be produced

all the ammonia will be consumed

HARD

11th CBSE

IMPORTANT

Earn 100

A mixture of ${CO}_{2}$ and $CO$ is passed over red-hot graphite when $1 mole$ of mixture changes to $33.6 L$ (converted to $STP$ ). Hence, mole fraction of ${CO}_{2}$ in the mixture is

100% studentsanswered this correctly

Important Questions on Some Basic Concepts of Chemistry

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 48

3.28 g

of a sample of pure copper when heated in presence of oxygen for some time forms black copper oxide

(CuO)

which weighs

3.92 g

. What approximate percent of copper remains unoxidized ?

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 49

An ore contains

1.24 %

of the mineral argentite,

{Ag}_{2} S

by mass. How many grams of this ore would have to be processed in order to obtain

1.0 g

of pure solid silver ?

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 50

The decomposition of a certain mass of

{CaCO}_{3}

gave

11.2 {dm}^{3}

{CO}_{2}

gas at

STP

. The mass of

KOH

required to completely neutralize the gas is

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 51

20.0 g

of magnesium carbonate sample decomposes on heating to give carbon dioxide and

8.0 g

of magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample ?(At. wt. of

Mg = 24 g {mol}^{- 1}

)

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 52

A mixture of

{CaCl}_{2}

and

NaCl

weighing

4.44 g

is treated with sodium carbonate solution to precipitate all the

{Ca}^{2 +}

ions as calcium carbonate. The calcium carbonate so obtained is heated strongly to get

0.56 g

CaO

. The percentage of

NaCl

in the mixture (atomic mass of

Ca = 40

) is

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 53

A mixture of ethane and ethene occupies

41 L

1 atm

and

500 K

. The mixture reacts completely with

\frac{10}{3} mole

of oxygen to produce

{CO}_{2}

and

H_{2} O

. The mole fraction of ethane and ethene in the mixture are

(R = 0.0821 L atm K^{- 1} {mol}^{- 1})

respectively

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 54

Excess of carbon dioxide is passed through

50 mL

0.5 M

calcium hydroxide solution. After the completion of the reaction, the solution was evaporated to dryness. The solid calcium carbonate was completely neutralised with

0.1 N

hydrochloric acid. The volume of hydrochloric acid required is (At. mass of carbon

= 40

)

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 55

In the reaction,

4 {NH}_{3} (g) + 5 O_{2} (g) \to 4 NO (g) + 6 H_{2} O (l)

, when

1 mole

of ammonia and

1 mole

O_{2}

are made to react to completion

A mixture of CO2 and CO is passed over red-hot graphite when 1 mole of mixture changes to 33.6 L (converted to STP). Hence, mole fraction of CO2 in the mixture is

Important Questions on Some Basic Concepts of Chemistry

Learn and Prepare for any exam you want !

A mixture of ${CO}_{2}$ and $CO$ is passed over red-hot graphite when $1 mole$ of mixture changes to $33.6 L$ (converted to $STP$ ). Hence, mole fraction of ${CO}_{2}$ in the mixture is