ECAT Chemistry Online Test With Answers

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ECAT Chemistry Online Test

Sr. # Questions Answers Choice
1 For which system does the equilibrium constant, KC has units of concentration
2 Decrease in temperature favour more dissolution of the salt Increase in temperature favour more dissolution of the salt Lowering pressure favour more dissolution of the salt Increasing pressure favour more dissolution of the salt
3 Shift reaction toward forward direction Shift reaction backward Lower the value of K<sub>c</sub> No change in reaction
4 Shift reaction toward forward direction Shift reaction backward Lower the value of K<sub>c</sub> No change in reaction
5 Le-chatlier's principle is applied on the reversible reaction in order to Determine the rate of reaction Predict the direction of reaction Determine the extent of reaction Find best conditions for favorable shifting the position of equilibrium
6 The optimum conditions of temperature and pressure to get maximum NH3form N2and H2gases is 2000°C and 10 atmosphere 0°C and 1 atmosphere 400°C and 200-300 atmosphere 200°C and 100 atmosphere
7 Forward Backward Already in equilibrium K<sub>c</sub>is never less
8 4 mole per dm<sup>3</sup> 2 mole per dm<sup>3</sup> 0.33 mole per dm<sup>3</sup> 0.67 mole per dm<sup>3</sup>
9 Le-chatlier's principle Only adding catalyst Decreasing pressure Decreasing temperature
10 Temperature is increased Pressure is increased HCl is added HCl is removed
11 KC = KP Kp = KcRT Kp = kc(RT)<sup>-2</sup> Kp = Kc(RT)<sup>-1</sup>
12 The value of K<sub>p</sub>falls with rise in temperature The value of K<sub>p</sub>falls with increasing pressure Addition of V<sub>2</sub>O<sub>5</sub>catalyst increase the concentration of SO<sub>3</sub> The value of K<sub>p</sub>is equal to K<sub>c</sub>
13 The value of Kpis greater than Kcfor a gaseous reaction when Number of molecules of products is greater than the reactants Number of molecules of reactants is greater than those of products Number of molecules of reactants and products equal Catalyst is added
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15 Moles per dm<sup>3</sup> Partial pressures Number of moles Mole fractions
16 Reaction occurs at STP Reaction is exothermic Reaction is endothermic Number of moles of production and reactant are same
17 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
18 Initial concentration of acetic acid Initial concentration of ethyl acetate Equilibrium concentration of acetic acid Equilibrium concentration of ethyl acetate
19 Law of mass action states that rate of chemical reaction is directly proportional to the product of active masses of the reactants. The term active mass means Mass in grams converted to products Number of moles Number of moles per dm<sup>3</sup>of reactants Total pressures of the reactants
20 Which one of the following has no units of its Kcvalue
21 Moles<sup>-2</sup>dm<sup>+6</sup> No units Mole dm<sup>-3</sup> Mole<sup>-1</sup>dm<sup>-3</sup>
22 Hydrogen gas and iodine vapours combine to form Hl at 425°C, the same composition of mixture is present if we start with decomposition of Hl. It suggests A static equilibrium Law of mass action A dynamic equlibrium Irreversible reaction
23 The solubility product of AgCl is 2.0 x 10-10mol2dm-6The maximum concentration of Ag+ions in the solution is 2.0 x 10<sup>-10</sup>mol dm<sup>-3</sup> 1.41 x 10<sup>-5</sup>mol dm<sup>-3</sup> 1.0 x 10<sup>-10</sup>mol dm<sup>-3</sup> 4.0 x 10<sup>-20</sup>mol dm<sup>-3</sup>
24 The pH of 10-3mole dm-3of an aqueous solution of H2SO4is 3.0 2.7 2.0 1.5
25 The value of K<sub>p</sub>falls with a rise in temperature The value of K<sub>p</sub>falls with increasing pressure Adding V<sub>2</sub>O<sub>5</sub>catalyst increase the equilibrium yield of sulphur trioxide equilibrium yield of sulphur trioxide The value of K<sub>p</sub>is equal to K<sub>c</sub>
26 For which system does the equilibrium constant. Kc has units of
27 HF is stable and does not decompose even at 2000°C HF is stable and slowly decomposes at 2000°C HF is strong acid HF produces equal moles of hydrogen and fluorine
28 Chemical equilibrium involving reactants and products in more than one phase is called Static Dynamic Homogeneous Heterogeneous
29 Reactions that proceed on both sides and never go to completion are called Irreversible reactions Reversible reactions Opposing reactions Spontaneous reactions
30 The rate at which a substance reacts is directly proportional to its active mass and the rate of reaction is directly proportional to the product of the active masses of reacting substances, is called Law of conservation of energy Le-Chateliers principle Law of mass action None of these
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