ECAT Chemistry Online Test With Answers

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ECAT Chemistry Online Test

Sr. # Questions Answers Choice
1 The chemical method used for determination of rate of reaction is Spectroscopic Conductiometric Refractometric Titration
2 Zero 253 sec 150 sec 500 sec
3 In the expression rate = K [A]a[B]bK is The order of reaction The speed of reaction The specific rate constant The overall order of reaction
4 The rate of reaction determined at a given time is called Average rate Instantaneous rate Specific rate Overall rate
5 With the progressive of the reaction the slope of the curve between concentration of product and time Gradually becomes more steep Gradually becomes less steep No change occurs in slope None of these occurs
6 The reaction rate is expressed in the units of Mol dm<sup>-3</sup>S<sup>-</sup> Mol dm<sup>-3</sup> Mol dm<sup>-3</sup>N<sup>-</sup> dm<sup>-3</sup>S<sup>-</sup>
7 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
8 The ionization constant of an acid is expressed in term of the following constant Kw Kn Ka Kb
9 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>
10 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
11 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
12 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
13 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
14 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
15 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
16 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>
17 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
18 The solubility of KCIO3salt in water is decreased by adding NaCIO<sub>3</sub> NaCI KCIO<sub>4</sub> KCI
19 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>
20 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
21 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>
22 Kavalue of HF acid is 6.7 x 10-15the acid is a Weak acid Moderately strong acid Strong acid Very weak acid
23 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%
24 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
25 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
26 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
27 The pH of 10-3mole dm-3of an aqueous solution of H2SO4is 3.0 2.7 2.0 1.5
28 An aqueous solution is neutral when its pH = 14 pH = zero pH = 7 Kw = 10<sup>-7</sup>
29 The ionic product of H+ions and OH-in water is called ionization constant of water Kw. The value of Kw at 25°C is 0.11 x 10<sup>-14</sup> 0.30 x 10<sup>-14</sup> 1.0 x 10<sup>-14</sup> 3 x 10<sup>-14</sup>
30 450°C 250°C 850°C 1000°C
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