12th Standard Chemistry Ionic Equilibrium English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

12th Standard

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Chemistry

Time : 00:20:00 Hrs
Total Marks : 20
20 x 1 = 20
1. Following solutions were prepared by mixing different volumes of NAOH of HCL different concentrations
1) 60 mL$\frac{M}{10}$HCl + 40mL$\frac{M}{10}$NaOH
2) 50 mL$\frac{M}{10}$HCl + 45mL$\frac{M}{10}$NaOH
3) 75 mL$\frac{M}{5}$HCl + 25mL$\frac{M}{5}$NaOH
4) 100 mL$\frac{M}{10}$HCl + 100mL$\frac{M}{10}$NaOH
pH of which one of them will be equal to 1?

(a)

iv

(b)

i

(c)

ii

(d)

iii

2. pH of a saturated solution of Ca(OH)2 is 9. The Solubility product (Ksp) of Ca(OH)2

(a)

0.5 ×10-15

(b)

0.25 ×10-10

(c)

0.125 ×10-15

(d)

0.5 ×10-10

3. Which will make basic buffer?

(a)

50 mL of 0.1M NaOH+25mL of 0.1M CH3COOH

(b)

100 mL of 0.1M CH3COOH+100 mL of 0.1M NH4OH

(c)

100 mL of 0.1M HCl+200 mL of 0.1M NH4OH

(d)

100 mL of 0.1M HCl+100 mL of 0.1M NaOH

4. Which of these is not likely to act as Lewis base?

(a)

BF3

(b)

PF3

(c)

CO

(d)

F

5. The aqueous solutions of sodium formate, anilinium chloride and potassium cyanide are respectively

(a)

acidic, acidic, basic

(b)

basic, acidic, basic

(c)

basic, neutral, basic

(d)

none of these

6. Equal volumes of three acid solutions of pH 1,2 and 3 are mixed in a vessel. What will be the H+ ion concentration in the mixture?

(a)

3.7 × 10-2

(b)

10-6

(c)

0.111

(d)

none of these

7. If the solubility product of lead iodide is 3.2 × 10-8, its solubility will be

(a)

2 × 10-3M

(b)

4 × 10-4M

(c)

1.6 × 10-5M

(d)

1.8 × 10-5M

8. H2PO4- the conjugate base of

(a)

PO43−

(b)

P2O5

(c)

H3PO4

(d)

HPO42-

9. Which of the following relation is correct for degree of hydrolysis of ammonium acetate?

(a)

$h=\sqrt { \frac { { K }_{ h } }{ C } }$

(b)

$h=\sqrt { \frac { { K }_{ h } }{ K_b } }$

(c)

$h=\sqrt { \frac { { K }_{ h } }{ { K }_{ a }.{ K }_{ b } } } \\$

(d)

$h=\sqrt { \frac { { { K }_{ a }.{ K }_{ b } } }{ { K }_{ h } } } \\$

10. Which of the following is not a Lewis acid?

(a)

SiCl4

(b)

AICl3

(c)

SO3

(d)

CO

11. Pick the strongest conjugate base among the following

(a)

Cl-

(b)

${ NO }_{ 2 }^{ - }$

(c)

${ SO }_{ 4 }^{ 2- }$

(d)

CH3COO-

12. Pick the odd one out

(a)

Cl-

(b)

CaO

(c)

SO2

(d)

CH-3

13. The conjugate base of NH-2 is

(a)

NH-

(b)

NH3

(c)

NH+3

(d)

NH2-

14. The relationship between degree of dissociation of a weak acid and its dissociation constant in a very dilute solution is

(a)

Ka = α2C

(b)

Ka$\frac{α^2C}{(1+α)}$

(c)

Ka$\frac{α^2}{(1+α)C}$

(d)

Ka$\frac{α}{C(1+α)}$

15. An example of basic buffer is

(a)

NH4OH and NH4CI

(b)

NH4OH and NaOH

(c)

NaOH and NH4Cl

(d)

NaOH and KOH

16. Buffer index is

(a)

$\beta =\frac { dB }{ p{ K }_{ a } }$

(b)

$\beta =\frac { dB }{ d(pH) }$

(c)

$\beta =\frac { dB }{ pH }$

(d)

$\beta =\frac { dB }{ pOH }$

17. The condition for a compound to be precipitated is

(a)

Ionic product = solubility product

(b)

Ionic product < solubility product

(c)

Ionic product > solubility product

(d)

Ionic product ≤ solubility product

18. Degree if dissociation is nearly equal to 1for

(a)

Strong acids and strong bases

(b)

Strong acids and weak bases

(c)

Weak acids and strong bases

(d)

Weak acids and weak bases

19. NH4OH is a weak base because

(a)

it has low vapour pressure

(b)

it is only partially ionised

(c)

it is completely ionised

(d)

it has low densit

20. When 10-6 mole of a monobasic strong acid is dissolved in one litre of solvent, the pH of the solution is

(a)

6

(b)

7

(c)

less than 6

(d)

more than 7