ECAT Pre Engineering Chemistry Chapter 8 MCQ Test With Answer

Under what condition of temperature and pressure the formation of atomic hydrogen from molecular hydrogen will be favourd

• High temperature and high pressure A
• Low temperature and low pressure B
• High temperature and low pressure C
• :Low temperature and high pressure D

An excess of aqueous silver nitrate is added to aqueous barium chloride and precipitate is removed by filtration. What are the main ions in the filtrate

• 
  A
• 
  B
• 
  C
• 
  D

The concentration of reactants is increased by x, then equilibrium constant K becomes

• ln K/x A
• K/x B
• K + x C
• K D

N₂ + 3H₂ ⇌2NH₃

The unit of K_c for tis reaction will be:

• mol² dm^-6

  A

• mol^-2 dm⁺⁶

  B

• mol dm^-3

  C

• mol^-1 dm⁺³

  D

• 1 A
• 10 B
• 5 C
• 0.33 D

• Initial concentration of acetic acid A
• Initial concentration of ethyl acetate B
• Equilibrium concentration of acetic acid C
• Equilibrium concentration of ethyl acetate D

I a chemical reaction equilibrium is said to have been established when :

• Rate of opposing reactions are equal. A
• Rate constants of opposing reactions are equal. B
• Opposing reactions stop. C
• Concentration of reactants and products are equal D

• Moles per dm³ A
• Partial pressures B
• Number of moles C
• Mole fractions D

The avtive mass of 64 g of HI in a two litre flask would be

• 2 A
• 1 B
• 5 C
• 0.25 D

• 8 A
• 4 B
• 9 C
• 3 D

If pH of buffer of 1 mole dm^-3of HCOOH + 0.1 mole dm^-3HCOONa having pKa = 3.78 is

• 1.78 A
• 2.78 B
• 3.78 C
• 4.78 D

For what value ofK_{c almost forward reaction is complete :}

• K_{c =} 10³⁰

  A

• K_{c =} 10^-30

  B

• K_{c =} 0

  C

• K_{c =} 1

  D

The state of equilibrium refers to

• State of rest A
• Dynamic state B
• Stationary state C
• State of inertness D

• 0.073 A
• 0.147 B
• 0.05 C
• 0.026 D

When a weak acid is dissolved in water or a weak base dissolved in water, then in both cases the conjugate acid base pair is produced. The ionization constants K_aand K_bof a pair are related with each other as

• K_a= K_b A
• K_a. K_b= K_w B
• K_a. K_w= K_b C
• K_b. K_w= K_a D

The rate of forward reaction is two times that of the reverse reaction at a given temperature and identical concentration, K equilibrium is

• 0.5 A
• 1.5 B
• 2.5 C
• 2.0 D

• Increase in concentration of 1 A
• Decrease in concentration of I₂ B
• Increase in temperature C
• Increase in total pressure D

Almost forward reaction is complete when value of k_{c :}

• Neither larger nor very small. A
• Very small. B
• Very large. C
• Negligible. D

The relation between Kc and Kp is

• 
  A
• 
  B
• 
  C
• 
  D

Which one of the following is not a buffer

• H₂CO₃+ NaHCO₃solution A
• H₃PO₄+ NaH₂PO₄solution B
• Hl + Nal solution C
• NH₄OH + NH₄CI solution D

• Forward A
• Backward B
• Already in equilibrium C
• K_cis never less D

• The value of K_pfalls with a rise in temperature A
• The value of K_pfalls with increasing pressure B
• Adding V₂O₅catalyst increase the equilibrium yield of sulphur trioxide equilibrium yield of sulphur trioxide C
• The value of K_pis equal to K_c D

K_bfor NH₄OH is 1.81 x 10^-5, then K_avalue of its conjugate base is

• 1.81 x 10⁺⁵ A
• 1.81 x 10^-9 B
• 5.5 x 10^-9 C
• 5.5 x 10^-10 D

Two moles of HI was heated in a sealed tube at 440°C till the equilibrium was reached. HI was found to be 22% decomposed. The equilibrium constant for dissociation is

• 0.282 A
• 0.0796 B
• 0.0199 C
• 1.99 D

pH of the human blood which is essentially maintained constant due to carbonates, biocarbonates, phosphates etc., is

• 7.00 A
• 7.25 B
• 7.35 C
• 7.47 D

An excess of aqueous silver nitrate is added to aqueous barium chloride and precipitate is removed by filtration. What are the main ion in filtrate?

• Ag⁺ and NO_3- only

  A

• Ag⁺ and Ba² and NO^-3

  B

• Ba² and NO^-3

  C

• Ba² and NO^-3 and Cl-

  D

• 0.5 A
• 4.0 B
• 2.5 C
• 0.25 D

In an exothermic reaction, a 10° rise in temperature will

• Decrease the value of equilibrium constant A
• Double the value of K_c B
• Not produce any change in K_c C
• Produce some increase in K_c D

ph of the buffer CH₃COOh + CH₃COONa is 3.76. If the mixture contains 1 molar acetic acid and 0.1 molar sodium acetate, then pKa of this buffer is

• 3.76 A
• 4.76 B
• 5.76 C
• 6.76 D

• Temperature is increased A
• Pressure is increased B
• HCl is added C
• HCl is removed D