Saturday, March 10, 2012

Acid -Base / Chemical Equilibrium


Acid  -Base  / Chemical  Equilibrium
1. The pH of solution  which contain 0.001 M  H+
A.4
B. 3
C. 11
D. 1
2. The concentration of H+ ion in water
A. 0.0000001 mol/dm3
B. 0.0001 mol/dm3
C. 0.00001 mol/dm3
D. 0.001  mol/dm3
3. Conjugate acid of weak base is the
A. Weakest  acid
B.Strongest acid
C.Moderate
D.None of above
4. The pH of buffer is equal pKa when concentration of salt is
A.           Concentration of salt and concentration of acid  is equal   
B.           Concentration of salt is twice of  concentration of acid    
C.           Concentration of salt is half than   concentration of acid    
D.           Concentration of salt is less than  concentration of acid     
5. When the equilibrium constant is greater than one . The equilibrium mixture contain concentration
A.                Reactant is greater than product
B.               Product is greater than reactant  
C.               Product is equal than reactant  
D.               Product is twice of reactant
6. A ratio between concentrations of reactant and product has greater than equilibrium constant at particular temperature. The reaction proceed in a
A.               Dynamic  Equilibrium state
B.               Before the equilibrium state
C.               After the  equilibrium
D.               None of above
7. The solubility of a sparingly soluble salt is “S”
CdCl2 ↔Cd2+  + Cl-1
The solubility product of salt
A.               S2
B.               2S3
C.               S3
D.               4S3
8. The equilibrium constant of reaction at particular temperature is 0.25M
2HI         ↔         H2           +             I2   
The equilibrium constant for will be
A . 0.25
B. 0.5
C. 4
D. 2.5
9. In Neutralization reaction of strong acid HCl and strong base NaOH. 10 ml of 0.1M HCl required ___________of 0.05M of NaOH  to complete neutralization   
A . 10 ml 
B.   5  ml 
C. 15  ml 
D. 20 ml
10. How many milliliter of 0.05M NaOH required to titrate of 0.1M HCl   
A . 5ml
B.  10 ml
C.  20 ml
D.  15 ml
11. Mixing 0.1 mol of NaOH, 0.1 mol of CH3COOH in  1 lit of water yields a solution, which:
               A.  is acidic
               B.  is neutral
               C.  is basic
               D. may be acidic, basic or neutral depending upon temperature
12. The dissociation constant of Pure  water is 14
               A. Increases with increase in temperature
               B.  Decreases with increase in temperature
               C.  Is constant & is independent of temperature
               D. increase in low temperature range but decreases in high temperature range

13.What will be the change in the pH of water if 10-3 mol of NaOH is added to 1.0 dm3 of water at 250C
               A. Increased by 3
               B. Increased by 4
               C. Decreased by 2
               D. Decreased by 4
14. When 1.0 cm3 of a weak acid solution is added to 100cm3 of a buffer solution
               A. the volume of the resulting mixture will be 100cm3
               B. there will be almost no change in the pH of solution
               C. the pH of the solution will increase noticeably
               D. the pH of the solution will decrease noticeably
15. Which salt does not form an acidic solution in water?
               A. MgCl2
               B. Na2CO3
               C. FeCl3
               D. NH4NO­3
16. Which species cannot act as a lewis acid ?
               A. BF3
               B.  AlCl3
               C. NH3
               D.  Fe2+
17. Three acids HA, HB & HC have the following Ka values
               i.   Ka of HA = 1 x 10-5
               ii.  Ka of  HB = 2 x 10-5
               iii. Ka HC    =1 x 10-6
What is the correct increasing order of acidic strength?
               A. HA< HB<, HC
               B. HC< HA< HB
               C. HC< HB< HA
               D. HB< HA< HC
18. Which of the following reagents could be added together to make a buffer solution?
               A. NaOH and CH3COOH
               B. CH3COONa and CH3COOH
               C.  NaOH & NaCH3COO
               D.  NH4Cl and NH3
19. Suppose that the equilibrium  A(aq)  + 2B(aq) ↔ C (aq) , is established from the original concentrations: [A]=[B]=[c]=0.10M at equilibrium it is found that [C] =0.040M. What is the value of the  equilibrium constant ,Kc  
A.  1.1
B.  5.2
               C.  0.19
D.  0.88
 20. At a temperature of about 4250C ,the equilibrium mixture contain  [H2] =0.10  ,[I2]= 0.10 and
[HI]= 0.70. If suddenly 0.050 mol/dm3 of H2, 0.050 mol/dm3 of I2 0.350 mol/dm3 of HI were added , the result would be that
A. more HI would from
               B.  the equilibrium would be shifted to the right
               C.  More H2  and I2 would from  
D. No net Chemical change would occur
21. According to Le Chatelier’s principle , an increase in temperature  would result in all of following EXCEPT :
A. an increase  in the value of K
B. an increase in the value of rate constant
C. an increase in the percentage decomposition of N2O5
D. an increase in the value of Activation energy  
22. Given : 2A(g) + B(g)   ↔ C (g) . If the equilibrium is established by starting  with equal numbers of moles of B and of C , no A . At equilibrium it is always true that :
               A.  [A]=[B]  
               B.  [B] =[C]
               C.   [A] >[C]
               D.  [B]>[C]
23.  Which of the following reaction has tendency to go to completion?
               A.  H2 (g) + O2(g)  ↔ 2H2O(g)            K= 1.7x 1027
B. N2 + O2  ↔ 2NO                         K= 5.0 x 10-31
C.  2HF  ↔ + F2 + H2                       K= 1.0x 10-13
D. 2NOCl   ↔ 2NO + Cl2                K= 1.7x 10-4
24. The term  “Ka for the ammonium ion” refers directly to  
A. NH3    + H2O ↔ NH+4   + OH-
B. NH3    + H3O+ ↔ NH+4 + H2O
C. NH++ H2O ↔ NH3    + H3O+
D. NH+4   + OH- ↔ NH3    + H2O
25. Which of the following  solutions has the smallest [H3O+]?
               A. 0.10M HCl
               B. 0.10M H2SO4
               C. 0.10M HNO3
               D. 0.10M NH4Cl

1 comment:

  1. sir pleasse send me the answer to these mcqs
    osama qadri m-2

    ReplyDelete