Some Basic Concepts of Chemistry Set-3

Question 1

The total number of electrons present in one molecule of methane is;

Accepted Answer

10

Answer

16

Answer

32

Answer

4

Question 2

Calculate the number of moles for each case respectively;
I. $22g$ $	ext{CO}_2$
II. $N_A/4$ Molecule of $	ext{CO}_2$
III. $22.4$ $	ext{L}$ $	ext{CO}_2$ at STP

Accepted Answer

0.5, 0.25, 1

Answer

0.25, 0.25, 0.25

Answer

0.25, 0.05, 0.05

Answer

0.05, 0.25, 0.25

Question 3

How many moles of carbon present in $88$ $g$ of $	ext{CO}_2$ [Atomic mass of $C = 12$ $amu$ and $O = 16$ $amu$]

Accepted Answer

2

Answer

3

Answer

4

Answer

5

Question 4

The number of molecules in $4.25gm$ ammonia is

Accepted Answer

$1.5 	imes 10^{23}$

Answer

$1.0 	imes 10^{23}$

Answer

$2.0 	imes 10^{23}$

Answer

$2.5 	imes 10^{23}$

Question 5

How many atoms are present in $28	ext{ grams of } 	ext{N}_2$?

Accepted Answer

$2	ext{ N}_A$

Answer

$1	ext{ N}_A$

Answer

$3	ext{ N}_A$

Answer

$4	ext{ N}_A$

Question 6

How many atoms are present in $0.046$ $g$ of ethanol?

Accepted Answer

$3.6 	imes 10^{21}$

Answer

$6 	imes 10^{20}$

Answer

$1.2 	imes 10^{21}$

Answer

$3 	imes 10^{21}$

Question 7

Number of g-atom of S present in $49$ $g$ $H_2SO_4$ are:

Accepted Answer

0.5

Answer

1

Answer

0.2

Answer

0.3

Question 8

Which of the following pair of gases contain the same number of molecules?

Accepted Answer

$16$ $g$ $	ext{O}_2$, $14$ $g$ $	ext{N}_2$

Answer

$8$ $g$ $	ext{O}_2$, $22$ $g$ $	ext{N}_2$

Answer

$28$ $g$ $	ext{N}_2$, $22$ $g$ $	ext{CO}_2$

Answer

$32$ $g$ $	ext{O}_2$, $32$ $g$ $	ext{N}_2$

Question 9

The mass of a molecule of water is

Accepted Answer

$3 	imes 10^{-26}$ $kg$

Answer

$3 	imes 10^{-25}$ $kg$

Answer

$1.5 	imes 10^{-26}$ $kg$

Answer

$2.5 	imes 10^{-26}$ $kg$

Question 10

How many moles of hydrogen atoms present in $34$ $g$ of $NH_3$?

Accepted Answer

6

Answer

5

Answer

4

Answer

7

Question 11

Calculate mole fraction of ethyl alcohol and water in a solution containing $46  g$ ethyl alcohol and $36  g$ water.

Accepted Answer

$\chi_{C_2H_5OH} = \frac{1}{3}$, $\chi_{H_2O} = \frac{2}{3}$

Answer

$\chi_{C_2H_5OH} = \frac{1}{2}$, $\chi_{H_2O} = \frac{1}{2}$

Answer

$\chi_{C_2H_5OH} = \frac{1}{4}$, $\chi_{H_2O} = \frac{3}{4}$

Answer

$\chi_{C_2H_5OH} = \frac{3}{4}$, $\chi_{H_2O} = \frac{1}{4}$

Question 12

A solution of $FeCl_3$ is $\frac{M}{30}$ its molarity for $Cl^-$ ion will be

Accepted Answer

$\frac{M}{10}$

Answer

$\frac{M}{90}$

Answer

$\frac{M}{30}$

Answer

$\frac{M}{5}$

Question 13

Which of the following has no units?

Accepted Answer

Mole fraction

Answer

Molarity

Answer

Normality

Answer

Molality

Question 14

Which of the following concentration term does not depend on temperature?

Accepted Answer

Molality

Answer

Molarity

Answer

Mass/volume

Answer

Normality

Question 15

The molarity of the solution containing 2.8% mass by volume solution of KOH (Given: atomic mass of $K = 39$) is:

Accepted Answer

$0.5  M$

Answer

$0.1  M$

Answer

$0.2  M$

Answer

$1  M$

Question 16

The number of moles of solute present in $2.0$ litres of $0.5M  NaOH$ solution is:

Accepted Answer

$1$

Answer

$2$

Answer

$4$

Answer

$0.1$

Question 17

Mass of $NaCl$ required to prepare $0.01  m$ aqueous solution in $1  kg$ water is

Accepted Answer

$0.585  g$

Answer

$0.01  g$

Answer

$58.8  g$

Answer

$5.88  g$

Question 18

$9.8  g$ of $H_2SO_4$ is present in $2$ litres of a solution. The molarity of the solution is:

Accepted Answer

$0.05  M$

Answer

$0.1  M$

Answer

$0.2  M$

Answer

$0.01  M$

Question 19

In one molal solution that contains $0.5$ mole of a solute, there is:

Accepted Answer

$500  g$ of solvent

Answer

$1000  g$ of solvent

Answer

$400  mL$ of solvent

Answer

$100  mL$ of solvent

Question 20

Number of moles of solute dissolved in $1000g$ of the solvent is called:

Accepted Answer

Molality

Answer

Molarity

Answer

Formality

Answer

Normality

Question 21

$N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$
$20  g$ $5  g$
Consider the above reaction, the limiting reagent of the reaction and number of moles of $NH_3$ formed respectively are:

Accepted Answer

$N_2$, $1.42$ moles

Answer

$H_2$, $1.42$ moles

Answer

$H_2$, $0.71$ moles

Answer

$N_2$, $0.71$ moles

Question 22

$3$ mol of $N_2$ and $2$ mol of $H_2$ were heated in a closed vessel. Maximum amount of $NH_3$ produced by their reaction is:

Accepted Answer

$22.66  g$

Answer

$18.52  g$

Answer

$20.57  g$

Answer

$24.31  g$

Question 23

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): The mass of the products formed in a reaction depends upon the limiting reactant.
Reason (R): Limiting reactant reacts completely in the reaction.
In the light of the above statements, choose the correct answer from the options given below:

Accepted Answer

Both A and R are true and R is the correct explanation of A

Answer

A is true but R is false

Answer

A is false but R is true

Answer

Both A and R are true but R is not the correct explanation of A

Question 24

$\frac{A}{2  	ext{mole}} + \frac{5B}{10  	ext{moles}} + \frac{8C}{4  	ext{mole}} ightarrow 6D + 7F$, in this reaction which is a limiting reagent?

Accepted Answer

C

Answer

A

Answer

B

Answer

None of these

Question 25

$2$ mole of $X$ (At. Wt. $= 36$) and $3$ mole of $Y$ (At. wt. $= 24$) are reacted to form the compound $X_3Y_2$. Then:

Accepted Answer

X is the limiting reagent

Answer

Y is the limiting reagent

Answer

No reactant is left over

Answer

$1$ mole $Y$ is left over

Question 26

$2  g$ of reactant A, $6  g$ of reactant C and $8  g$ of reactant D reacts to form product B. Find the limiting reagent. (Given; Molar mass (in gm/mol) of A $= 28$, B $= 34$, C $= 66$, D $= 16$)
Reaction: $2A + 4C + 3D = 8B$

Accepted Answer

C

Answer

D

Answer

A

Answer

Cannot be determined

Question 27

The number of atoms present in one mole of an element is equal to Avogadro number. Which of the following contains the greatest number of atoms?

Accepted Answer

$12	ext{g He}$

Answer

$4	ext{g He}$

Answer

$46	ext{g Na}$

Answer

$0.40	ext{g Ca}$

Question 28

How many atoms are present in $16	ext{ grams of } 	ext{O}_2$?

Accepted Answer

$1	ext{ N}_A$

Answer

$0.5	ext{ N}_A$

Answer

$2	ext{ N}_A$

Answer

$4	ext{ N}_A$

Question 29

How many atoms are present in $4	ext{ grams of } 	ext{H}_2$?

Accepted Answer

$4	ext{ N}_A$

Answer

$1	ext{ N}_A$

Answer

$2	ext{ N}_A$

Answer

$3	ext{ N}_A$

Question 30

How many atoms are present in $44	ext{ grams of } 	ext{CO}_2$?

Accepted Answer

$3	ext{ N}_A$

Answer

$1	ext{ N}_A$

Answer

$2	ext{ N}_A$

Answer

$4	ext{ N}_A$

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Some Basic Concepts of Chemistry Set-3

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