ECAT Chemistry Chapter 8 Chemical Equilibrium Online Test With Answers

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ECAT Chemistry Chapter 8 Chemical Equilibrium Online Test

Sr. # Questions Answers Choice
1 pH of water is 7, if 0.01 M NaOH is added, than its pH is 12 14 zero 10
2 pH of 1 molar NaOH is 7 zero 14 10
3 pKb value of NH4OH is 4.74. If the concentration of NH4OH is 1 molar containing 0.1 molar NH4Cl, then pH of this buffer will be 3.74 10.26 4.74 9.26
4 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 4.76 5.76 6.76
5 The best buffer is prepared when molar concentrations of the salt and acid are equal, then its pH and pKa value are related pH = pKa pH < pKa pH > pKa pH x pKa = 14
6 pH and pKa of the buffer are related by Henderson equation which is
7 Kbvalue of NH4OH is 1.81 x 10-5and its conjugate acid has Ka= 5.7 x 10-10pKb of the base is 4.74, pKa of its conjugate acid is -4.74 4.74 10 9.26
8 strength of an acid can be determined by P<sup>ka</sup> P<sup>kp</sup> P<sup>oH</sup> P<sup>kw</sup>
9 Addition of solid NaHCO3in water causes ionization of NaCHO3its Ka= 4.7 x 10-1. Then this solution has character Acidic Very weakly basic Alkaline Neutral
10 The ionization constant of an acid is expressed in term of the following constant Kw Kn Ka Kb
11 A solution having pH = 4 its OH-ion concentration in mole dm-3is 1.0 x 10<sup>-4</sup> 1.0 x 10<sup>-10</sup> 1.0 x 10<sup>-14</sup> 1 x 10<sup>0</sup>
12 Which one of the following is not a buffer H<sub>2</sub>CO<sub>3</sub>+ NaHCO<sub>3</sub>solution H<sub>3</sub>PO<sub>4</sub>+ NaH<sub>2</sub>PO<sub>4</sub>solution Hl + Nal solution NH<sub>4</sub>OH + NH<sub>4</sub>CI solution
13 Which one of the following is a buffer HCI + NaCI solution CH<sub>3</sub>COOH + CH<sub>3</sub>COONH<sub>4</sub>solution H<sub>2</sub>SO<sub>4</sub>+ CaSO<sub>4</sub>solution CH<sub>3</sub>COOH + CH<sub>3</sub>COONa
14 Base buffer solution can be prepared by mixing Weak acid and its salt Strong acid and its salt with weak base Weak base and its salt with strong acid Strong base and its salt with weak acid
15 Whenever a week base is dissolved in water, it give its conjugate acid. similarly a weak acid in water produces its conjugate base. This conjugate acid-base pair concept is stated by Law of mass action Le-charlier's principle Common ion effect Lowery Bronsted concept
16 If the difference of pKa values of the two acids is 2, then Acid with smaller pKa is 10 times stronger acid Acid with greater pKa is 10 times stronger acid Acid with smaller pKa is 100 times stronger acid Acid with greater pKa is 100 times stronger acid
17 0.1 MHCI has pH = 1.0, it is about 100 times stronger than acetic acid. Then pH of acetic acid will be 0.1 2.0 1.3 3.0
18 Units of Kw are Mole dm<sup>-3</sup> Mole<sup>2</sup>dm<sup>-3</sup> Mole<sup>2</sup>dm<sup>-6</sup> Mole<sup>2</sup>dm<sup>-3</sup>
19 Which of the following solution have zero pH 1 M HCI MH<sub>2</sub>SO<sub>4</sub> 0.1 M HNO<sub>3</sub> 1 M CH<sub>3</sub>COOH
20 The solubility of KCIO3salt in water is decreased by adding NaCIO<sub>3</sub> NaCI KCIO<sub>4</sub> KCI
21 Kbfor NH4OH is 1.81 x 10-5, then Kavalue of its conjugate base is 1.81 x 10<sup>+5</sup> 1.81 x 10<sup>-9</sup> 5.5 x 10<sup>-9</sup> 5.5 x 10<sup>-10</sup>
22 On passing HCI gas through a saturated solution of commercial sodium chloride, pure crystals of NaCI are precipitated due to Increase in pH of the solution Decrease in pH of the solution Common ion effect Increase in ionization of NaCl
23 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 Kaand Kbof a pair are related with each other as K<sub>a</sub>= K<sub>b</sub> K<sub>a</sub>. K<sub>b</sub>= K<sub>w</sub> K<sub>a</sub>. K<sub>w</sub>= K<sub>b</sub> K<sub>b</sub>. K<sub>w</sub>= K<sub>a</sub>
24 Kavalue of HF acid is 6.7 x 10-15the acid is a Weak acid Moderately strong acid Strong acid Very weak acid
25 In 1000 molecules of 0.001 M acetic acid the number of H+ions is 12.6, then its percentage of ionization is 1.33% 1.26% 12.6 1%
26 Acetic acid is 1.33% ionized, In 1000 molecules of 0.1 M acetic acid the number of H+ions is 1.33 13.3 1.33 1
27 A solution of NaOH has pH = 13, then concentration of NaOH is 10<sup>-13</sup>M 10<sup>13</sup>M 10<sup>-1</sup>M 10<sup>+1</sup>M
28 A solution has pH = 0, its H+ion concentration is 1 x 10<sup>-14</sup> 1 x 10<sup>14</sup> 1 x 10<sup>1</sup> 1
29 The pH of 10-3mole dm-3of an aqueous solution of H2SO4is 3.0 2.7 2.0 1.5
30 An aqueous solution is neutral when its pH = 14 pH = zero pH = 7 Kw = 10<sup>-7</sup>
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