Tips and Tricks of The Day


Record Limit : 

    2020-Apr-10
Ex: If the equilibrium constant of the reaction 2HI ⇌ H2+I2 is 0.25, then the equilibrium constant of the reaction H2+I2 ⇌ 2HI would be:
A) 1.0         
B) 4.0
C) 3.0         
D) 2.0
Explanation: Kfor reaction 2HI ⇌H2+I2is 0.25      K2 for reaction H2+I2⇌ 2HI will be
K2 = 1/K1 = 1 / 0.25 = 4 Because IInd reaction is reverse of Ist.
    2020-Apr-09
Ex: A square frame of side L is dipped in a liquid. On taking out, a membrane is formed. If the surface tension of the liquid is T, the force acting on the frame will be:
A) 2 TL    
B) 10 TL
C) 8 TL    
D) 4 TL
Explanation:
Force on each side =2TL (due to two surfaces)             
∴ Force on the frame = 4(2TL) = 8TL
    2020-Apr-08
Ex: The kinetic theory of gases perdicts that total kinetic energy of a gaseous assembly depends on:
A) Pressure of the gas        
B) Temperature of the gas               
C) Volume of the gas          
D) Pressure, volume and temperature of the gas
Explanation: K.E = 3/2 RT it means that K.E depends upon T (absolute temperature) only.
    2020-Apr-07
Ex: The critical temperature of water is higher than that of O2 because H2O molecule has:
A) Fewer electrons than oxygen
B) Dipole moment
C) V-shape
D) Two covalent bonds
Explanation: Critical temperature of water is more than O2 due to its dipole moment (Dipole moment of water = 1.84 D; Dipole moment of O2 = zero D)
    2020-Apr-06
Ex: An electric dipole of moment p is placed in the position of stable equilibrium in uniform electric field of intensity E. It is rotated through an angle θ from the initial position. The potential energy of electric dipole in the final position is:
A) pEcosθ
B) pEsinθ
C) pE(1−cosθ)
D) -pEcosθ
Explanation: Potential energy of dipole in electric field U=−PEcosθ; where q is the angle between electric field and dipole.
    2020-Apr-03
Ex: If the inversion temperature of a gas is −80oC, then it will produce cooling under Joule-Thomson effect at:
A) 298 K    
B) 273 K
C) 193 K    
D) 173 K
Explanation: If inversion temperature is 80oC = 193oK then the temperature, at which it will produce cooling under Joule Thomson's effect, would be below inversion temperature except 173oK all other values given as.
    2020-Apr-02

Ex: The kinetic theory of gases perdicts that total kinetic energy of a gaseous assembly depends on:

A) Pressure of the gas        
B) Temperature of the gas               
C) Volume of the gas          
D) Pressure, volume and temperature of the gas
Explanation: K.E = 3/2RT it means that K.E depends upon T (absolute temperature) only.
    2020-Apr-01
Ex: If a diamagnetic solution is poured into a U-tube and one arm of this U-tube placed between the poles of a strong magnet with the meniscus in a line with the field, then the level of the solution will:
A) Rise                                          
B) Remain as such
C) Oscillate slowly                   
D)  Fall
Explanation: Because, diamagnetic substance, moves from stronger magnetic field to weaker field.
 
    2020-Mar-31
Ex: The rate law for the reaction RCl + NaOH(aq) → ROH + NaCl is given by Rate = K1[RCl]. The rate of the reaction will be:
A) Doubled on doubling the concentration of sodium hydroxide
B) Unaffected by increasing the temperature of the reaction
C) Decreased on increasing the temperature of the reaction
D) Halved on reducing the concentration of alkyl halide to one half
Explanation:
R = K[RCl], if [RCl] =1/2, then rate = R/2
    2020-Mar-30
Ex: Electrolytes when dissolved in water dissociate into their constituent ions. The degree of dissociation of an electrolyte increases with:
A) Increasing concentration of the electrolyte
B) Decreasing concentration of the electrolyte
C) Decreasing temperature
D) Presence of a substance yielding a common ion
Explanation: Because the degree of dissociation is inversely proportional to the concentration of the electrolyte.