NEET chemistry

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Question
CBSEENCH11008472

Consider the change in oxidation state of Bromine corresponding to different emf values as shown in the diagram below :

BrO4- 1.82BrO3-1.5 VHBrO1.595Br21.0652 VBr-

Then the species undergoing disproportionation is

  • BrO3-

  • BrO4-

  • HBrO

  • Br2

Solution

C.

HBrO

Calculate Ecell° corresponding to each compound undergoing disproportionation reaction. The reaction for which Ecell° comes out +ve is spontaneous.

HBrO   Br2Eo = 1.595 V, SRP (cathode)HBrO    BrO3-Eo = - 1.5 V, SOP (anode)2HBrO   Br2 + BrO3-Ecello = SRP (cathode)- SRP (anode)= 1.595 - 1.5= 0.095 VEcell0> 0  Go < 0 [spontaneous]

Sponsor Area

Question
CBSEENCH11008474

Which one of the following conditions will favour maximum formation of the product in the reaction,

A2 (g) + B2 (g)       X2 (g)r H = - XkJ?

  • Low temperature and high pressure

  • Low temperature and low pressure

  • High temperature and low pressure

  • High temperature and high pressure

Solution

A.

Low temperature and high pressure

A2 (g)+ B2 (g)   X2 (g);  H = - xkJ

On increasing pressure equilibrium shift in a direction where number of moles decreases i.e. forward direction.

On decreasing temperature, equilibrium shift n exothermic direction i.e., forward direction.

So high pressure and lower temperature favour maximum formation of product.

Question
CBSEENCH11008475

The bond dissociation energies of X2, Y2 and XY are in the ratio of 1 : 0.5: 1. ΔH for the formation of XY is –200 kJ mol–1. The bond dissociation energy of X2 will be

  • 200 kJ mol-1

  • 100 kJ mol-1

  • 400 kJ mol-1

  • 800 kJ mol-1

Solution

D.

800 kJ mol-1

Let B.E of x2,y2 and xy are x kJ mol-1, 0.5 x kJ mol-1 and x kJ mol-1 respectively

12x2 + 12y2  xy;H = - 200 kJ mol-1H = - 200 = Σ(B.E)reactant - Σ(B.E)product = 12  x (x) +12 x (0.5)x-[1x (x)]On solving we get, B.E of X2 = x = 800 kJ mol-1

Question
CBSEENCH11008476

The correction factor ‘a’ to the ideal gas equation corresponds to

  • Density of the gas molecules

  • Volume of the gas molecules

  • Forces of attraction between the gas molecules

  • Electric field present between the gas molecules

Solution

C.

Forces of attraction between the gas molecules

In the real gas equation, P + an2V2 (V-nb) = nRT van der Waal's constant, 'a' signifies intermolecular forces of attraction.

Question
CBSEENCH11008477

Which one is a wrong statement?

  • Total orbital angular momentum of electron in 's' orbital is equal to zero

  • An orbital is designated by three quantum numbers while an electron in an atom is designated by four quantum numbers

  • The value of m for dz2 is zero

  • The electronic configuration of N atom is

Solution

D.

The electronic configuration of N atom is

According to Hund's Rule of maximum multiplicity, the correct electronic configuration of N-atom is