General Questions and Answers

3 KMnO4 can be prepared from K MnO4 as per the reaction 3 MnO 2H O2 MnO MnO2 4OH The reaction can go to completion by removing OH ions by adding 1 KOH 2 CO 3 SO 4 HCI

A balloon filled with a gas absorbs 1kJ of heat expands against a constant pressure of 1 atmosphere from a volume of 20 litres to 23 litres The value of AE would be approximately Question Type Single Correct Type 1 600 J 2 1200 J 3 696 J

46 SCQ en C The BC13 is a planar molecule whereas NC13 is pyramidal because A N Cl bond is more covalent than B Cl bond B C D B Cl bond is more polar than N Cl bond Nitrogen atom is smaller than boron Correct Answer BC13 has no lone pair but NC13 has a lone pair of electrons

49 SCQ In borax the number of B 0 B and B OH bonds are respectively A five and four B four and five C three and four D en five and five Correct Answer

Q No 70 For the decomposition 2N205 g 4NO2 g O g activation energy Ea N205 g 2NO2 g O2 g activation energy Ea then of N O5 g it is given that Ea 2Ea Ea Ea Ea Ed

In a vessel O gas molecules were adsorbed on solid surface causing its partial pressure to decrea from 1 atm to 0 5 atm Given NA 6 1023 volume of the vessel 2 24L T 273K total area of solid surface 10 cm Number of active sites per unit area 10 4 m Find the number of O2 molecules adsorbed per active site

Which of the following reactions is not correct according to the law of conservation of mass A 2Mg s O g 2MgO s C3Hg s O g CO g H O g B C D 4 s 50 g P4010 s CH4 g 20 g CO g 2H O g

Q 36 4 1 00 19 For a first order reaction A products the concentration of A changes from 0 1 M to 0 025 M in 40 minutes The rate of reaction when the concentration of A is 0 01 M is O 3 47 10 M min 0 5

Potassium sorbate C6H7KO is an additive used to prevent molding of cheese Its conjugate acid monoprotic has Ka 1 74x10 5 Find the pH of an aqueous solution containing 2 55 g of potassium sorbate in 500 0 mL Select one O a 10 65 O b 8 65 O c 3 11 O d 4 76 O e 2 55

Q 11 4 1 00 19 Bauxite ore is concentrated by O Froth floatation Electromagnetic separation O Chemical separation

Which one of the following statements is true for all the alkali metals A B Their nitrates decompose on heating to give NO and 02 D Their carbonates decompose on heating to give CO and the metal oxide C They react with oxygen to give mainly the oxides M 0 Correct Answer They react with halogens to give halides MX

Q 35 4 For a reaction xg yg z g the half life period is 10 min in what period of time would the concentration of X be reduce to 10 of original concentration 20 min O 33 min mi 1 00 24

Q 35 O Silver C 4 In electro refining of metal the impure metal is made the anode and a strip of pure metal the cathode during the electrolysis of an aqueous solution of a complex metal salt This method cannot be used for refining of Copper 1 00 03 O

Sodium bicarbonate is reacted with concentrated hydrochloric acid at 37 C and 1 00 atm The reaction of 6 00 kg of sodium bicarbonate with excess L of CO2 hydrochloric acid under these conditions will produce Select one O a 1 82 x 104 O b 1 09 x 10 O c 8 70 x 10 O d 2 85 x 104 O e 1 82 x 10

27 A 25 0 mm x 40 0 mm piece of gold foil is 0 25 mm thick The density of gold is 19 32 g cm How many gold atoms are in the sheet Atomic weight Au 197 0 b 1 5x 10 23 c 4 3 1021 23 a 7 7 10 d 1 47 x 1022

The correct order of viscosity of ethanol ethylene glycol and glycerol is A Ethanol Ethylene Glycol Glycerol B Ethanol Glycerol Ethyleneglycol C Ethylene Glycol Ethanol Glycerol Correct Answer D Glycerol Ethylene Glycol Bl

A concentration cell is a galvanic cell in which O The electrode material and the solution are made up of same substances but electrode and or electrolyte concentration are different Each half cell is made of electrode material and solutions that are composed of different substances and different concentrations Ecell 0 The nernst equation reduces to F 2 303 RT

Q 17 The rate constant for the first order reaction is 60s How O4 6 10 s 4 1 00 28 much time will it take to reduce the concentration of the reaction to 1 16 M value 4 6 10 s 4 6 x 10 s

15 mg radioactive sample 90 disintegrate in 4 years 99 9 disintegration will be in 90 afea atar m 15 mg af at 99 9 faufa A 4 years 4 f B 8 years 8 d C 12 years 12 ad D 16 years 16 Your Answer B

Q 9 The mass of carbon anode consumed giving only carbon dioxide in the production of 270 kg of aluminium metal from bauxite by the hall process is Atomic mass of Al 27 O 180kg 4 1 00 24 270 kg

11 Why is HCI not used to make the medium acidic in oxidation reactions of KMnO4 in acidic medium 1 Both HCI and KMnO4 act as oxidising agents 2 KMnO4 oxidises HCl into Cl which is also an oxidising agent 3 KMnO4 is a weaker oxidising agent than HCL 4 KMnO4 acts as a reducing agent in the presence of HCI

5 In a saturated solution of the sparingly soluble strong electrolyte AgIO molecular mass 283 the equilibrium which sets in is AgIO3 s Ag aq IO3 aq If the solubility product constant Ksp of AgIO3 at a given temperature is 1 0 108 what is the mass of AgIO contained in 100 mL of its saturated solution 1 28 3 10 3 1 0 107 g 2 28 3 10 3 g 4 1 0 104 g

The most abundant elements by mass in the body of a healthy human adult are Oxygen 61 4 Carbon 22 9 Hydrogen 10 0 and Nitrogen 2 6 The weight which a 75 kg person atoms are replaced would gain if all 1 by 2H atoms is A 7 5 kg B 10 kg C c 15 kg D 37 5 kg H

Q 37 The reaction 25O g O g 250 g is carried out in a 1dm vessel and 2d m vessel separately The ratio of the reaction velocities will be O 1 8 O 1 4 C 4 1 00 19 4 1

The rate constant of the reaction A B is 0 6 10 3 mole per second If the concentration of A is 5 M then concentration of B after 20 minutes is 2015 RS a 1 08 M c 0 36 M b 3 60 M d 0 72 M

Q 24 4 1 O 1 g 00 21 O Plot of log x m against log p is a straight line inclined at an angle of 45 When the pressure is 0 5 atm and Freundlich parameter k is 10 the amount of solute adsorbed per gram of adsorbent will be log 5 0 6990

68 Chromium plating can involve the electrolysis of an electrolyte of an acidified mixture of chromic acid and chromium sulphate If during electrolysis the article being plated increases in mass by 2 6 g and 0 6 dm of oxygen are evolved at an inert anode the oxidation state of chromium ions being discharged must be assuming Cr 52 and 1 mole of gas at room temperature and pressure occupies a volume of 24 dm a 1 c 1 b zero d 2

3 1 0 2 4 None of these 7 A graph between log t 2 and log a abscissa a being the initial concentration of A in the reaction for reaction A Product the rate law is log a 1 2 k 3 d A dt d A dt d A dt d A Slope 1 log a K K A Chemical k K A KIAN

In a sample of blood at 25 C H 4 6 x 108 M Find the molar concentration of OH and indicate whether the sample is acidic basic or neutral OH i M blood is A certain acid has a pKa equal to 4 88 Is this aci stronger or weaker than acetic acid which has a pKa of 4 74 What is the value of Ka for this acid It is a acid Ka Why do small highly charged hydrated metal ions form acidic solutions Small highly charged hydrated metal ions form acidic solutions because the water hydrates the metal ion then the high charge density of the metal ion turn hond this in the oxygen hydrogen

Q 33 4 1 00 05 N g 3H g 2NH g 22 kcal The activation energy for the forward reaction is 50 kcal What is the activation energy for the backward reaction 72 kcal O 28 kcal 28 kcal

4 a It minimum wavelength in emission spectrum of Li 2 in 51 94 HE paschen series is P then what is the maximum wave length in emission spectrum of He in balmer series 1 P 2 P 4 P 30 F 2 Haf txa 1 P

Q 28 O Na SO4 Among the electrolytes Na2SO4 CaCl2 Al2 SO4 NH4Cl the most effective coagulation agent for Sb S sol is O CaCl O Al SO4 3 4 1 NU 00 18

A gaseous compound of nitrogen and hydrogen contains 12 5 by mass of hydrogen The density of the compound relative to hydrogen is 16 The molecular formula of the compound is A B C NH N H NH3 NU

Which of them is not a part of Dalton s atomic theory A B C D Atoms cannot be divided created or destroyed The number of protons in an atom is its atomic number In chemical reactions atoms are combined separated or rearranged All matter is composed of extremely small particles called atoms

The partial pressure of ethane over a solution containing 6 56 103 g of ethane is 1 bar If the solution contains 5 00 10 2 g of ethane then what shall be the partial pressure of the gas Delhi 2013 C AI 2012 C

7 The centre of mass of a system of particles does not depend on 1 Position of the particles 2 Relative distances between the particles 3 Masses of the particles 4 Forces acting on the particles

Q 10 moderate 4 1 00 20 Alkaline earth metals are not found free in nature because of O Their high b p O Their low b p Thermal instability 7 Their great chemical

220 45 The quantum numbers of four electrons are as follows n 0 Electron 1 3 1 Electron 2 3 Electron 3 4 iv Electron 4 3 0 2 1 0 0 2 46 fra t S NI NIH NI NIN Batch Chemical Arithmetic Atomic Structure Solid State 2 1 Electron 1 3 n Electron 2 3 ii Electron 3 4 iv Electron 4 3 0 0 0 Nie nie nie wie

Q 3 4 1 00 19 Addition of FeCl to K Fe CN in dilute and cold solution gives O Prussian blue sol O Fe Fe CN Sol O Positive sol C

oblem 3 1 08 g of copper wire was allowed to react with nitric acid The resulting solution was dried and ignited when 1 35 g of copper oxide was obtained In another experiment 2 30 g of copper oxide was heated in presence of hydrogen yielding 1 84 g of copper Show that the above data are in accordance with law of constant proportion

For the two moving particles A and B if the momentum of particle A having wavelength 1 is double of particle B ther the wavelength of particle B is 2 0 5 4

D Consider the reaction 2x g 3y g 2z g At constant temperature and volume partial pressure of x p varies as follows Time min 0 100 200 Order of the reaction is 1 O 3 1 px mm Hg 800 400 200 2 0 5 4 2

Q 31 For the Ch the initial concentration of was 0 20 mol L and the concentration after 20 min was 0 18 mol L Then the rate of formation of 1 in mol L would be 4 1 00 43 reaction 21 12 2 CF 1810 4

If decomposition reaction A g B g follows first order kinetics then the graph of rate of formation R of B against time t will be KU 2 1 3 14 4 h Decomposition of NH NO aq into N g and 2H O 1 is first order reaction Which of the following graph is correct 1 0 288 2 0 577 3 1 154 4 none If above where you

The standard reduction potential of normal calomel electrode and reduction potential of saturated calomel electrodes are 0 27 and 0 33 volt respectively What is the concentration of CI in saturated solution of KCI 1 0 1 M 2 0 01 M 3 0 001 M 4 None

3 85 The value of AH in kJ for the reaction will be 6 2 6 2 4 24 2 2 CS 1 4NOCI g CCI 1 2SO g 2N g if AHO NOCI y AHO SO r An AHO CS x X AH CC Z 1 x 4y z 2r 2 r z 4y x 3 2r z 4y x 4 x 4y z 2r K 2 6 4 5 3 15 85 3K 1 CS 1 4NOCI g CCI 1 25O g 2N g AHO CS x AHO NOCI Y AHO CCI z AHO SO r 1 x 4y z 2r 2 r z 4y x 3 2r z 4y x 4 x 4y z 2r

Which of the following statements is not correct O a Standard deviation is a measure of precision b All types of equilibrium are dynamic OC Percent dissociation of HF increases with increasing its concentratic d Buffer activity is most active at pH pkc

Bombardment on nucleus A by a particle leads to its artificial disintegration in two ways i and ii as shown Products X Y and Z respectively are Oproton neutron positron O neutron positron proton Oproton positron neutron Opositron proton neutron 27 13 i 30 14B X 30 15 C Y 30 14D Z

5 The chromium in a 1 0 g sample of chromite FeCr2O4 was oxidized to Cr 6 state by fusion with Na2O2 The fused mixture was treated with excess of water and boiled to destroy the excess of peroxide After acidification the sample was treated with 50 mL of 0 16 M FeSO4 solution 3 67 mL of 0 05 M Cr O solution was required to oxidize the Fe2 ion left unreacted Determine the mass of chromite in the original sample Cr 52 Fe 56

Q 19 O 0 5 0 O 1 250 4 O 12 5 M 1 K for a zero order reaction is 2 102 mol L sec If the concentration of the reactant after 25 sec is 0 5 M the initial concentration must have been 00 31 000