NEET > Some Basic Concepts of Chemistry

Explore popular questions from Some Basic Concepts of Chemistry for NEET. This collection covers Some Basic Concepts of Chemistry previous year NEET questions hand picked by popular teachers.


Q 1.    

Correct4

Incorrect-1

Suppose the elements X and Y combine to form two compounds XY{tex}_2{/tex} and X{tex}_3{/tex}Y{tex}_2{/tex}. When 0.1 mole of XY{tex}_2{/tex} weighs 10 g and 0.05 mole of X{tex}_3{/tex}Y{tex}_2{/tex} weighs 9 g, the atomic weights of X and Y are

{tex} 40,30 {/tex}

B

{tex} 60,40 {/tex}

C

{tex} 20,30 {/tex}

D

{tex} 30,20 {/tex}

Explanation

Q 2.    

Correct4

Incorrect-1

What is the mass of the precipitate formed when 50 mL of 16.9{tex} \% {/tex} solution of {tex} \mathrm { AgNO } _ { 3 } {/tex} is mixed with 50 mL of 5.8{tex} \% \ \mathrm { NaCl } {/tex} solution?
{tex} ( \mathrm { Ag } = 107.8 , \mathrm { N } = 14 , \mathrm { O } = 16 , \mathrm { Na } = 23, {/tex} {tex} \mathrm { Cl } = 35.5 ) {/tex}

A

3.5{tex} \mathrm { g } {/tex}

7{tex} \mathrm { g } {/tex}

C

14{tex} \mathrm { g } {/tex}

D

28{tex} \mathrm { g } {/tex}

Explanation

Q 3.    

Correct4

Incorrect-1

If Avogadro number {tex} N _ { A } , {/tex} is changed from {tex} 6.022 \times 10 ^ { 23 } \mathrm { mol } ^ { - 1 } {/tex} to {tex} 6.022 \times 10 ^ { 20 } \mathrm { mol } ^ { - 1 } , {/tex} this would change

the mass of one mole of carbon

B

the ratio of chemical species to each other in a balanced equation

C

the ratio of elements to each other in a compound

D

the definition of mass in units of grams.

Explanation

Q 4.    

Correct4

Incorrect-1

The number of water molecules is maximum in

A

1.8 gram of water

B

18 gram of water

18 moles of water

D

18 molecules of water.

Explanation

Q 5.    

Correct4

Incorrect-1

A mixture of gases contains {tex} \mathrm { H } _ { 2 } {/tex} and {tex} \mathrm { O } _ { 2 } {/tex} gases in the ratio of {tex} 1 : 4 ( w / w ) . {/tex} What is the molar ratio of the two gases in the mixture?

A

{tex} 16 : 1 {/tex}

B

{tex} 2 : 1 {/tex}

C

{tex} 1 : 4 {/tex}

{tex} 4 : 1 {/tex}

Explanation

Q 6.    

Correct4

Incorrect-1

Equal masses of {tex} \mathrm { H } _ { 2 } , \mathrm { O } _ { 2 } {/tex} and methane have been taken in a container of volume {tex} V {/tex} at temperature {tex} 27 ^ { \circ } \mathrm { C } {/tex} in identical conditions. The ratio of the volumes of gases {tex} \mathrm { H } _ { 2 } : \mathrm { O } _ { 2 } : {/tex} methane would be

A

{tex} 8 : 16 : 1 {/tex}

B

{tex} 16 : 8 : 1 {/tex}

{tex} 16 : 1 : 2 {/tex}

D

{tex} 8 : 1 : 2 {/tex}

Explanation



Q 7.    

Correct4

Incorrect-1

When 22.4 litres of {tex} \mathrm { H } _ { 2 ( g ) } {/tex} is mixed with 11.2 litres of {tex} \mathrm { Cl } _ { 2 ( g ) } {/tex} , each at {tex} \mathrm { S.T.P }{/tex}, the moles of {tex} \mathrm { HCl } _ { ( g ) } {/tex} formed is equal to

1 mol of {tex} \mathrm { HCl } _ { ( g ) } {/tex}

B

2 mol of {tex} \mathrm { HCl } _ { ( \mathrm { g } ) } {/tex}

C

0.5 mol of {tex} \mathrm { HCl } _ { ( g ) } {/tex}

D

1.5 mol of {tex} \mathrm { HCl } _ { ( \mathrm { g } ) } {/tex}

Explanation

Q 8.    

Correct4

Incorrect-1

1.0 g of magnesium is burnt with 0.56 g O{tex}_2{/tex} in a closed vessel. Which reactant is left in excess and how much? (At.wt. Mg = 24,O = 16 )

{tex} \mathrm { Mg } , 0.16 \mathrm { g } {/tex}

B

{tex} \mathrm { O } _ { 2 } , 0.16 \mathrm { g } {/tex}

C

{tex} \mathrm { Mg } , 0.44 \mathrm { g } {/tex}

D

{tex} \mathrm { O } _ { 2 } , 0.28 \mathrm { g } {/tex}

Explanation

Q 9.    

Correct4

Incorrect-1

{tex} 6.02 \times 10 ^ { 20 } {/tex} molecules of urea are present in 100 mL of its solution. The concentration of solution is

A

0.001{tex} \mathrm { M } {/tex}

B

0.1{tex} \mathrm { M } {/tex}

C

0.02{tex} \mathrm { M } {/tex}

0.01{tex} \mathrm { M } {/tex}

Explanation

Q 10.    

Correct4

Incorrect-1

In an experiment it showed that 10mL of 0.05{tex} \mathrm { M } {/tex} solution of chloride required 10 mL of 0.1{tex} \mathrm { M } {/tex} solution of {tex} \mathrm { AgNO } _ { 3 } {/tex} , which of the following will be the formula of the chloride {tex} ( X {/tex} stands for the symbol of the element other than chlorine)

A

{tex} X _ { 2 } \mathrm { Cl } _ { 2 } {/tex}

{tex} X \mathrm { Cl } _ { 2 } {/tex}

C

{tex} X \mathrm { Cl } _ { 4 } {/tex}

D

{tex} X _ { 2 } \mathrm { Cl } {/tex}

Explanation

Q 11.    

Correct4

Incorrect-1

Which has the maximum number of molecules among the following?

A

44{tex} \ \mathrm { g }\ \mathrm { CO } _ { 2 } {/tex}

B

48{tex}\ \mathrm { g } \ \mathrm { O } _ { 3 } {/tex}

8{tex} \ \mathrm { g } \ \mathrm { H } _ { 2 } {/tex}

D

64{tex}\ \mathrm { g } \ \mathrm { SO } _ { 2 } {/tex}

Explanation

Q 12.    

Correct4

Incorrect-1

The number of atoms in 0.1 mol of a triatomic gas is {tex} \left( N _ { A } = 6.02 \times 10 ^ { 23 } \mathrm { mol } ^ { - 1 } \right) {/tex}

A

{tex} 6.026 \times 10 ^ { 22 } {/tex}

{tex} 1.806 \times 10 ^ { 23 } {/tex}

C

{tex} 3.600 \times 10 ^ { 23 } {/tex}

D

{tex} 1.800 \times 10 ^ { 22 } {/tex}

Explanation

Q 13.    

Correct4

Incorrect-1

25.3{tex} \mathrm { g } {/tex} of sodium carbonate, {tex} \mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 } {/tex} is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, {tex} \mathrm { Na } ^ { + } {/tex} and carbonate ions, {tex} \mathrm { CO } _ { 3 } ^ { 2 - } {/tex} are respectively (Molar mass of {tex} \mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 } {/tex}= 106 g mol{tex}^ { - 1 }{/tex})

A

0.955{tex} \mathrm { M } {/tex} and 1.910{tex} \mathrm { M } {/tex}

1.910{tex} \mathrm { M } {/tex} and 0.955{tex} \mathrm { M } {/tex}

C

1.90{tex} \mathrm { M } {/tex} and 1.910{tex} \mathrm { M } {/tex}

D

0.477{tex} \mathrm { M } {/tex} and 0.477{tex} \mathrm { M } {/tex}

Explanation


Q 14.    

Correct4

Incorrect-1

10 {tex} \mathrm { g } {/tex} of hydrogen and 64{tex} \mathrm { g } {/tex} of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be

A

3 mol

4 mol

C

1 mol

D

2 mol

Explanation

Q 15.    

Correct4

Incorrect-1

What volume of oxygen gas {tex} \left( \mathrm { O } _ { 2 } \right) {/tex} measured at {tex} 0 ^ { \circ } \mathrm { C } {/tex} and 1{tex} \mathrm { atm } {/tex} , is needed to burn completely 1{tex} \mathrm { L } {/tex} of propane gas {tex} \left( \mathrm { C } _ { 3 } \mathrm { H } _ { 8 } \right) {/tex} measured under the same conditions?

5{tex} \mathrm { L } {/tex}

B

10{tex} \mathrm { L } {/tex}

C

7{tex} \mathrm { L } {/tex}

D

6{tex} \mathrm { L } {/tex}

Explanation

Q 16.    

Correct4

Incorrect-1

How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of {tex} \mathrm { PbO } {/tex} and 3.2 g {tex} \mathrm { HCl } {/tex} ?

A

0.011

0.029

C

0.044

D

0.333

Explanation

Q 17.    

Correct4

Incorrect-1

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave {tex} \mathrm { C } , 38.71 \% {/tex} and {tex} \mathrm { H } , 9.67 \% {/tex} . The empirical formula of the compound would be

A

{tex} \mathrm { CHO } {/tex}

B

{tex} \mathrm { CH } _ { 4 } \mathrm { O } {/tex}

{tex} \mathrm { CH } _ { 3 } \mathrm { O } {/tex}

D

{tex} \mathrm { CH } _ { 2 } \mathrm { O } {/tex}

Explanation

Q 18.    

Correct4

Incorrect-1

An element, X has the following isotopic composition:
{tex}^{200}X : 90\%\ \ \ \ ^{199}X : 8.0\% \ \ \ \ ^{202}X : 2.0\% {/tex}
The weighted average atomic mass of the naturally occurring element {tex}X{/tex} is closest to

A

201 amu

B

202 amu

C

199 amu

200 amu

Explanation

Q 19.    

Correct4

Incorrect-1

The maximum number of molecules is present in

15 L of {tex}\mathrm {H_2}{/tex} gas at STP

B

5 L of {tex} \mathrm { N } _ { 2 } {/tex} gas at {tex} \mathrm { STP } {/tex}

C

0.5 g of {tex} \mathrm { H } _ { 2 } {/tex} gas

D

10{tex} \mathrm { g } {/tex} of {tex} \mathrm { O } _ { 2 } {/tex} gas.

Explanation


Q 20.    

Correct4

Incorrect-1

Which has maximum molecules?

A

7 g {tex} \mathrm { N } _ { 2 } {/tex}

2 g {tex}\mathrm { H } _ { 2 } {/tex}

C

16 g {tex}\mathrm { NO } _ { 2 } {/tex}

D

16 g {tex}\mathrm { O } _ { 2 } {/tex}

Explanation

Q 21.    

Correct4

Incorrect-1

Percentage of Se in peroxidase anhydrous enzyme is 0.5{tex} \% {/tex} by weight (at. wt. = 78.4 ) then minimum molecular weight of peroxidase anhydrous enzyme is

{tex} 1.568 \times 10 ^ { 4 } {/tex}

B

{tex} 1.568 \times 10 ^ { 3 } {/tex}

C

{tex} 1.568 {/tex}

D

{tex} 2.136 \times 10 ^ { 4 } {/tex}

Explanation

Q 22.    

Correct4

Incorrect-1

Molarity of liquid HCl, if density of solution is 1.17 g/cc is

A

36.5

B

18.25

32.05

D

42.10

Explanation

Q 23.    

Correct4

Incorrect-1

Specific volume of cylindrical virus particle is {tex} 6.02 \times 10 ^ { - 2 } \mathrm { cc } / \mathrm { g } {/tex} whose radius and length are 7{tex} {\text{Å}} {/tex} and 10{tex} {\text{Å}} {/tex} respectively. If {tex} N _ { A } = 6.02 \times 10 ^ { 23 } {/tex} , find molecular weight of virus.

{tex} 15.4 \ \mathrm { kg } / \mathrm { mol } {/tex}

B

{tex} 1.54 \times 10 ^ { 4 } \mathrm { kg } / \mathrm { mol } {/tex}

C

{tex} 3.08 \times 10 ^ { 4 } \mathrm { kg } / \mathrm { mol } {/tex}

D

{tex} 3.08 \times 10 ^ { 3 } \mathrm { kg } / \mathrm { mol } {/tex}

Explanation

Q 24.    

Correct4

Incorrect-1

In quantitative analysis of second group in laboratory, {tex}H_{2}S{/tex} gas is passed in acidic medium for precipitation. When Cu{tex} ^ { 2 + } {/tex} and Cd{tex} ^ { 2 + } {/tex} react with {tex} KCN , {/tex} then for product, true statement is

A

{tex} \mathrm { K } _ { 2 } \left[ \mathrm { Cu } ( \mathrm { CN } ) _ { 4 } \right] {/tex} more soluble

B

{tex} \mathrm { K } _ { 2 } \left[ \mathrm { Cd } ( \mathrm { CN } ) _ { 4 } \right] {/tex} less stable

{tex} \mathrm { K } _ { 3 } \left[ \mathrm { Cu } ( \mathrm { CN } ) _ { 2 } \right] {/tex} less stable

D

{tex} \mathrm { K } _ { 2 } \left[ \mathrm { Cd } ( \mathrm { CN } ) _ { 3 } \right] {/tex} more stable.

Explanation


Q 25.    

Correct4

Incorrect-1

Volume of {tex} \mathrm { CO } _ { 2 } {/tex} obtained by the complete decomposition of 9.85{tex} \mathrm { g } {/tex} of {tex} \mathrm { BaCO } _ { 3 } {/tex} is

A

2.24{tex} \mathrm { L } {/tex}

1.12{tex} \mathrm { L } {/tex}

C

0.84{tex} L {/tex}

D

0.56{tex} \mathrm { L } {/tex}

Explanation