NAT II Biological Science Chemistry With Answers

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NAT II Biological Science Chemistry

Sr. # Questions Answers Choice
1 In cold countries ethylene glycol is added to water in radiators of cars during winter. It results in Lowering in b.pt. Reducing viscity Reducing specific heat Lowering in freezing pt.
2 What happens when isotonic solution of a (mol. wt. 342) and B (mol. wt 60) are put in to communication through semiperme-able membrane? Transference of solvent from solution A to that of B take place Transference of solvent from solution B to that of A takes place No transference of solvent from solution A to that of B takes place Change in temperature of solutions takes place.
3 The freezing point of 1 molal NaCl solution assuming NaCl to be 100% dissociated in water in -1.86<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 18px; background-color: rgb(255, 255, 248);">°C</span> -3.72<span style="font-family: &quot;Times New Roman&quot;; font-size: 18px; color: rgb(34, 34, 34); background-color: rgb(255, 255, 248);">°C</span> +1.86<span style="font-family: &quot;Times New Roman&quot;; font-size: 18px; color: rgb(34, 34, 34); background-color: rgb(255, 255, 248);">°C</span> +3.72<span style="font-family: &quot;Times New Roman&quot;; font-size: 18px; color: rgb(34, 34, 34); background-color: rgb(255, 255, 248);">°C</span>
4 Which of the following value ofΔHf represent that product is least stable? -94.0 kcal mol<sup>-1</sup> -231.6 kcal mol<sup>-1</sup> +21.4 kcal mol<sup>-1</sup> +64.8 kcal mol<sup>-1</sup>
5 All the naturally occurring processes proceed spontaneously in a direction which lead to Decrease of entropy Increase of enthalpy Increase of free energy Decrease of free energy
6 ΔHneutralisationis always positive Negative Zero Positive or negative
7 The heat evolved in combustion of rhombic and monoclinic sulphur are -70960 and -71030 cal mol-1respectively. What will be heat of conversion of rhombic sulphur to monoclinic? 70960 calories 71030 calories -70 calories +70 calories
8 Hess's law deals with Changes in heat or reaction Rate of reaction Equilibrium constant Influence of pressure on volume of a gas.
9 An endothermic reaction is one in which the reacting substances Have more energy than the products Have less energy than the products Have the same energy as the products Are at a higher temperature than the products.
10 Which of the following units represents largest amount of energy? Calorie Joule Erg Electron vol.
11 Evaporation of water is An exothermic change an endothermic change A process where no heat changes occur A process accompanied by chemical reaction.
12 Inter molecular forces in solid hydrogen are Covalent forces Van der Waal forces or London dispersion forces Hydrogen bonds All of these.
13 According to MO theory, the species O+2 Bond order of 2.5 Three unpaired electrons Diamagnetic character Stability lower then O<sub>2</sub>
14 The bond angle H-O-H in ice is closest to 120<span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 18px; background-color: rgb(255, 255, 248);">° . 28'</span> 60<span style="font-family: &quot;Times New Roman&quot;; font-size: 18px; color: rgb(34, 34, 34); background-color: rgb(255, 255, 248);">°</span> 90<span style="font-family: &quot;Times New Roman&quot;; font-size: 18px; color: rgb(34, 34, 34); background-color: rgb(255, 255, 248);">°</span> 109<span style="font-family: &quot;Times New Roman&quot;; font-size: 18px; color: rgb(34, 34, 34); background-color: rgb(255, 255, 248);">°</span>
15 The carbon atoms in calcium carbide are held by Ionic bonds Sigma bonds 2 covalent, one co-ordinate bond <i>2</i><span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 224);"><i>π</i> <i>and one</i></span><span style="color: rgb(34, 34, 34); font-family: &quot;Times New Roman&quot;; font-size: 24px; text-align: center; background-color: rgb(255, 255, 248);"><i>α bond</i></span>
16 Outermost shells of two elements X and Y have two and six electrons respectively. If they combine, the expected formula of compound will be XY X<sub>2</sub>Y X<sub>2</sub>Y<sub>3</sub> XY<sub>2</sub>
17 Which of the following geometry is associated with the compound in which the central atom assumes sp3d hybridization? Planar Pyramidal Angular Trigonal bipyramidal
18 Covalent compounds are soluble in Polar solvents Non-polar solvents Concentrated acids All solvents
19 Among the alkaline earth metals the element forming predominantly covalent compounds is Be Mg Sr Calcium
20 Hydrogen chloride molecule contains Covalent bond Double bond Co-ordinate bond Electrovalent bond
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