Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

The pair of compound which cannot exists together in solution is

  • NaHCO3 and NaOH

  • Na2CO3 and NHCO3

  • Na2CO3 and NaOH

  • NaHCO3 and NaCl


A.

NaHCO3 and NaOH

Acidic salt (NaHCO3) and base (NaOH) cannot exist together in solution.


2.

Which has maximum number of atoms ?

  • 24 g of C

  • 56 g of Fe

  • 26 g of Al

  • 108 g of Ag


A.

24 g of C

No. of atoms in 24g of                              C =2412×6.02 ×1023 = 2 ×6.02×1023No. of atoms in 56 g of                           Fe= 5656× 6.02 ×1023No. of atoms in 26 g of Al= 2627 × 6.02×1023 6.02×1023   No. of atoms in 108 g of                                      Ag =108108×6.02 ×1023 =6.02×1023                           


3.

4.6 x 1022 atoms of an element weigh 13.8g. The atomic weight of that element is

  • 290

  • 180

  • 34.4

  • 10.4


B.

180

4.6 × 1022 atoms weigh = 13.8 gHence, 6.02 × 1013 atoms will weigh=13.8 × 6.02×10234.6 ×1022= 180.6g (molar mass)


4.

Number of lone pair (s) in XeOF4 is/are

  • 0

  • 2

  • 1

  • 3


C.

1

The number of lone pair in XeOF4 is one (1). The structure of XeOF4 is given as follows :

      


5.

Which of the following has the smallest number of molecules ?

  • 0.1 mole of CO2 gas

  • 11.2 L of CO2 gas at STP

  • 22 g of CO2 gas

  • 22.4 x 10mL of CO2 gas at STP


A.

0.1 mole of CO2 gas

(a) 0.1 mole of CO2

(b)11.222.4 = 0.5 mole of CO2

(c) 2244 = 0.5 mole of CO2

(d) 22.4 ×10322400= 1 mole of CO2

Hence, the number of moles of CO2 is least ie, 0.1.


6.

Which one ofthe following compounds has sp2 hybridisation ?

  • CO2

  • SO2

  • N2O

  • CO


B.

SO2

In SO2 molecule, S is sp2-hybridised

S(16)  = 1s2, 2s2, 2p6, 3s2, 3p4


7.

In homogeneous catalysis

  • the reactants, catalyst and products are in the same phase.

  • the catalyst and reactants are in the same phase.

  • the catalyst and products are in the same phase.

  • the reactants and products are in the same phase.


B.

the catalyst and reactants are in the same phase.

Homogenous catalysis - When the reactants and catalyst are in the same phase, the catalysis is known as homogenous catalysis.
Example: 2KClO3(s) MnO2(s)2KCl(s) + 3O2(g)


8.

Identify the least stable ion amongst the following.

  • Li-

  • Be-

  • B-

  • C-


C.

B-

Li-= 1s2, 2s2 (In it all sub-shells are saturated so, it is stable).

Be- = 1s2, 2s2, 2p1(very much less stable).

B- = 1s2, 2s2, 2p2 (less stable)

C- = 1s2, 2s2, 2p3 (stable due to presence of half-filled 2p-subshell).


9.

A liquid is in equilibrium with its vapour at it's boiling point. On the average, the molecules in two phases have equal

  • inter- molecular forces

  • potential energy

  • kinetic energy

  • total energy


C.

kinetic energy

In liquid  vapour, equilibrium the rate at which molecules escape from the liquid surface to gaseous phase equals to rate at which molecules in the gas phase strike the surface and becomes the part of liquid. Hence, the molecules in the two phases have equal kinetic energy.


10.

For the chemical reaction 3X(g)+ Y(g) X3Y (g), the amount of X3Y at equilibrium is affected by

  • temperature and pressure

  • temperature only

  • pressure only

  • temperature, pressure and catalyst


B.

temperature only

Equilibrium is  affected by temperature and pressure due to change in heat as well as change in volume of substances.