Basic Concepts in Chemistry MCQs – III

201)The number of molecules in 16 g of methane is

202)50 ml 10 N , 25 ml 12 N HCl and 40 ml 5 N were mixed together and the volume of the mixture was made 1000 ml by adding water. The normality of the resultant solution will be
a) 1 N
b) 2N
c) 3N
d) 4N

203)The number of atoms in 4.25 g of is approximately

204)A molal solution is one that contains 1 mole of a solute in
a) 1000 g of the solvent
b) one litre of the solvent
c) one litre of the solution
d) 22.4 litres of the solution

205)One mole of calcium phosphide on reaction with excess of water gives
a) one mole of phosphine
b) two moles of phosphoric acid
c) two moles of phosphine
d) one mole of phosphorus pentoxide.

206)A 100 ml solution of 0.1 N HCl was titrated with 0.2 N NaOH solution. The titration was discontinued after adding 30 ml of NaOH solution. The remaining titration was completed by adding 0.25 N KOH solution. The volume of KOH required for completing the titration is
a) 70 ml
b) 32 ml
c) 35 ml
d) 16 ml

207)Assuming full decomposition, the volume of released at STP on heating 9.85 g of (atomic mass, Ba = 137) will be
a) 0.84 L
b) 2.24 L
c) 4. 06 L
d) 1.12 L

208)The specific heat of a metal is 0.16. Its approximate atomic weight would be
a) 32
b) 16
c) 40
d) 64

209)The weight of a molecule of the compound is

210)The number of water molecules present in a drop of water (volume 0.0018ml) at room temperature is

211)A compound contains atoms of three elements A, B and C . If the oxidation number of A is +2 , B is +5 and that of C is –2, the possible formula of the compound is

212)Which of the following contains the most number of atoms?
d) 0.33 mol of CO2

213)The nmber of g of oxygen in 32.2 g is
a) 20.8
b) 22.4
c) 2.24
d) 2.08

214)An aqueous solution of 6.3 g of oxalic acid dihydrate is made up to 250 ml. The volume of 0.1 N NaOH required to completely neutralize 10 ml of this solution is
a) 40 ml
b) 20 ml
c) 10 ml
d) 4 ml

215)Which has the highest mass?
a) 50 g of iron
c) 0.1 g atom of Ag.

216)How many moles of helium gas occupy 22.4 litres at and 1 atmosphere?
a) 0.11
b) 0.90
c) 1.0
d) 1.11

217)The number of atoms in 4.25 g of is approximately

218)If 224 ml of a triatomic gas X3 has a mass of 1 g at 273 K and 1 atm pressure, then the mass of one atom X, is
c) 5.56 X 10 -23

219)How many molecules of an ideal gas are there in 1 ml of the gas if temperature is and pressure is 3 atm.?

220)If the isotopic distribution of C- 12 and C-14 is 98% and 2% respectively, then the number of C-14 atoms in 12 g of carbon is
a) 1.2 x 10 22

221)0.22 g of a substance when vaporized displaced of air measured over water at 293 K and 755 mm. Pressure and aq. tension is 17.4 mm. Then the gram molecular weight of the substance will be
a) 222.2 g
b) 232.3 g
c) 121.1 g
d) 127.5 g

222)If a compound contains two oxygen atoms and four carbon atoms and the number of hydrogen atoms is double that of carbon atoms, the density of its vapour will be
a) 88
b) 44
c) 132
d) 72

223)An oxide of a metal (m) contains 40 % by mass of oxygen. The metal (M) has a relative mass of 24. The empirical formula of the oxide is

224)4.0 g of caustic soda ( mol. mass 40) contains the same number of sodium ions as are present in

225)Which of the following contains the greatest mass of chlorine ?


A sample of calcium carbonate has the following percentage composition

Ca=40%; C=12%; O= 48%

If the law of constant proportions is true, then the weight of calcium in 4 g of a sample of calcium carbonate from another source will be

a) 0.016 g
b) 0.16 g
c) 1.6 g
d) 16 g

227)Two elements X and Y have atomic weights of 14 and 16. They form a series of compounds A, B,C,D and E in which for the same amount of element X, Y is present in the ratio 1:2:3:4:5. If the compound A has 28 parts by weight of X and 16 parts by the weight of Y then the compound C will have 28 parts by weight of X and
a) 32 parts by weight of Y
b) 48 parts by weight of Y
c) 64 parts by weight of Y
d) 80 parts by weight of Y

228)The mass of CaO that shall be obtained heating 20 kg of 90% pure lime-stone is
a) 11.2 kg
b) 8.4 kg
c) 10.08 kg
d) 16.8 Kg

229)X g of Ag was dissolved in and the solution was treated with excess of NaCl when 2.87 g of AgCl was precipitated. The value of X is
a) 1.08 g
b) 2.16 g
c) 2.70 g
d) 1.62 g

230)What mass of calcium chloride in grams would be enough to produce 14.35 g of AgCl ?(At. Mass Ca=40; Ag=108)
a) 5.55 g
b) 8.295 g
c) 16.59 g
d) 11.19 g

231)The weight of slaked lime taken as pure Ca(OH)2 necessary to decompose completely 1.07 g of ammonium chloride is
a) 0.74 g
b) 1.48 g
c) 7.4 g
d) 0.37 g

232)The weight of NaCI which on complete reaction with H2S04 gives 0.1 mole of HCl is
a) 5.85 g
b) 0.585 g
c) 1.170 g
d) 11.70 g

233)2.6 g of mixture of calcium carbonate and magnesium carbonate is strongly heated to a constant weight of 1.3 g. The atomic weights of calcium and magnesium are 40 and 24 respectively. State which of the following is the weight of calcium carbonate in the original mixture.
a) 980 mg
b) 400 mg
c) 1.75 g
d) 0.74 g

234)The mass of produced when carbon dioxide is bubbled through 500 mL of 0.5 M will be
a) 10 g
b) 20 g
c) 50 g
d) 25 g

235)If LPG is a mixture of butane and isobutane, then the amount of oxygen that would be required for combustion of 1 Kg of it will be
a) 1.8 Kg
b) 2.7 Kg
c) 4.5 Kg
d) 3.58 Kg

236)12 L of and 11.2 L of are mixed and exploded. The composition by volume of the resulting mixture is
a) 24 L of HCl

237)If potassium chlorate is 80% pure, then 48 g of oxygen would be produced from (atomic mass of K= 39)

238)What volume of 1 M NaOH solution would be just sufficient to convert to 12 g of sodium dihydrogen phosphate (mol. wt. 120) into tri sodium phosphate ?

239)The mass of oxygen that would be required to produce enough CO to completely reduce ( at mass Fe=56) is
a) 240 g
b) 480 g
c) 720 g
d) 960 g

240)@ 4.35 g of a sample of pyrolusite when heated with conc. HCl gave chlorine. The chlorine when passed through potassium iodide solution liberated 6.35 g of iodine. The percentage purity of the pyrolusite sample is
a) 40
b) 50
c) 60
d) 70

241)Which one of the following stands for ?
a) deka
b) centi
c) hecta
d) deci

242)In the Haber process, gaseous nitrogen and hydrogen react to form ammonia whose volume with reference to the total volume of the reactants under the same conditions of temperature and pressure would be
a) one fourth
b) one half
c) the same
d) three fourth

243)0.84 g of a metal hydride contains 0.042 g of hydrogen. The equivalent weight of the metal hydride is
a) 80
b) 40
c) 60
d) 20

244)A metallic oxide contains 60 % of the metal. The equivalent weight of the metal is
a) 12
b) 24
c) 40
d) 48

245)When a metal is burnt, its weight is increased by 24 percent. The equivalent weight of the metal will be
a) 2.0
b) 24.0
c) 33.3
d) 76.0

246)The specific heat of a metal is 0.11 and its equivalent weight is 18. 61. Its exact atomic weight is
a) 58.2
b) 29.1
c) 55.83
d) 27. 91

247)The vapour density of a volatile chloride of a metal is 95 and the specific heat of the metal is 0.13. The equivalent weight of the metal will be approximately
a) 6
b) 12
c) 18
d) 24

248)0.84 g of the carbonate of a metal M gave on heating 0.40 g metal oxide. The specific heat of the metal is 0.25. The atomic weight of the metal would be
a) 12
b) 24
c) 36
d) 48

249)In alkaline medium reacts as follows ,Therefore, the equivalent weight of will be
a) 31.6
b) 52.7
c) 7.0
d) 158.0

250) The equivalent weight of in this reaction
a) 98
b) 49
c) 32.66
d) 24.5

251)12 g of an alkaline earth metal gave 14. 8 g of its nitride. The atomic weight of the metal is
a) 20
b) 12
c) 40
d) 14.8

252)30 mL of an acid is neutralized by 15 mL of 0.2 N alkali. The strength of the acid is
a) 0.1 N
b) 0.2 N
c) 0.3 N
d) 0.4 N

253)0.16 g of a dibasic acid required 25 ml of decinormal NaOH solution for complete neutralization. The molecular weight of the acid will be
a) 32
b) 64
c) 128
d) 256

254)@ To change the strength of 25 mL of 0.15 M HCl to 0.1 M, the quantity of water that is to be added is
a) 37.5 ml
b) 12.5 ml
c) 25 ml
d) 50 ml

255)@ 5.3 g of have been dissolved to make 250 cc of the solution. The normality of the resulting solution will be
a) 0.1 N
b) 0.2 N
c) 0.4 N
d) 0. 8 N

256)100 cc of 0.1 N HCl have been mixed with 100 cc of 0.2 N NaOH. The heat evolved will be
a) 57.1 kJ
b) 5.71 kJ
c) 0.571 kJ
d) 1.142 kJ

257)In an experiment 20 ml of decinormal HCl solution was added to 10 ml of a decinormal solution. AgCl was precipitated out and the excess acid was titrated against a decinormal NaOH solution. Volume of NaOH required for this back titration is
a) 10 ml
b) 5 ml
c) 20 ml
d) 30 ml

258)If iodized salt contains 1% of KI and a person takes 2 g of the salt every day the iodide ions going into his body every day would be approx.

259)Caffeine has a molecular weight of 194. If the molecule contains 28.9% by mass of nitrogen, the number of atoms of nitrogen in one molecule of caffeine is
a) 4
b) 6
c) 2
d) 3

260)@ A mixture of , and is enclosed in a vessel of one litre capacity at . The ratio of partial pressure of gasses is 1:4:2. Total pressure of the gaseous mixture is 2660 mm. The number of molecules of oxygen present in the vessel is

261) If the density of liquid water is then the effective volume occupied by one molecule of water in the liquid state is approximately
d) cm3

262)The mass of carbon present in 0.5 mole of is
a) 1.8 g
b) 18 g
c) 3.6 g
d) 36 g

263)Zinc sulphate contains 22. 65 % of Zinc and 43. 9% of water of crystallization. If the law of constant proportions is true, then the weight of zinc required to produce 20 g of the crystals will be
a) 43.5 g
b) 4.53 g
c) 0.453 g
d) 453 g

264)What volume of gas at S.T.P should be dissolved in 100 ml of water to prepare a 2.5 molal (2.5 m) ammonium hydroxide solution?
a) 0.056 litres
b) 0.56 litres
c) 5.6 litres
d) 11.2 litres

265)If n g of a substance X reacts with m g of substance Y to form p g of substance R and q g of substance S. which of the following relationships is true?
a) n-m = p-q
b) n + m = p + q
c) n = m
d) p = q

266)A hydrocarbon contains 86% carbon. 488 ml of the hydrocarbon in the gaseous state weighs 1. 68 g at S.T.P. Then the hydrocarbon could be an
a) alkane
b) alkene
c) alkyne
d) arene

267)100 ml of 0.1 N hypo decolorised the iodine generated by the addition of x g of crystalline copper sulphate to excess of KI. The value of x is ( molecular wt. of CuSO4 is 250)
a) 5.0 g
b) 1.25 g
c) 2.5 g
d) 4 g

268)The element whose atom has a mass of is
a) Boron
b) Calcium
c) Silver
d) Zinc

269)The unit is equivalent to
d) none of these

270)From the following masses, the one which is expressed to the nearest milligram is
a) 16 g
b) 16.4 g
c) 16.428 g
d) 16. 4284 g

271)The mass of a mole of electrons is
a) 0.20 mg
b) 0.02 mg
c) 0.55 mg
d) 1.00 mg

272)The mass of nitrogen per gram hydrogen in the compound hydrazine is exactly one and half times the mass of nitrogen in the compound ammonia. The fact illustrates:
a) the law of conservation of mass
b) the multiple valency of nitrogen
c) the law of multiple proportions.
d) The law of definite proportions

273)The number of gram atoms of oxygen present in 0.3 gram mole of is
a) 0.6
b) 1.8
c) 1.2
d) 3.6

274)A gaseous mixture contains and in equimolecular proportions. The weight of 2.24 liters of this mixture at N.T.P is
a) 4.6 g
b) 1.6 g
c) 2.3 g
d) 23 g

275)An electric discharge is passed through a mixture containing 0.1 mole of H2 and 0.1 mole of O2. The molar composition of the resultant mixture, H2:O2:H2O, will be
a) 0:0.05:0.1
b) 0:0:0.15
c) 0.05:0:0.05
d) 0:0.05:0.05

276)@ The ratio of the amount of needed to precipitate all the metal ions from 100 ml of 1 M and 100 ml of 1M will be
a) 1:1
b) 1:2
c) 2:1
d) None of these

277)Which of the following do not have three significant figures?
b) 0.25

278)Which of the following has the most number of significant figures?
a) 0.050
b) 0.50
c) 5.0
d) 50.0

279)Which one of the following statements is not correct about the three states of matter ie. solid, liquid and gaseous?
a) Molecules of a solid possess the least energy whereas those of a gas possess the highest energy
b) Molecules in solids are more closely packed than in gases
c) Gases like liquids possess definite volumes
d) Molecules of a solid possess vibratory motion

280)A volume of 1 m 3 is equal to

281)Which one of the following is not a unit of pressure?
a) Newton
b) Torr
c) Pascal
d) Bar

282)One atmosphere is numerically equal to approximately

283)Which one of the following plots will be a parabola at constant temperature?
a) P vs 1/V
b) PV vs P
c) V vs P
d) None of these

284) Which of the following are Fertilizers?

I. Calcium amm. nitrate

II. Urea

III Calcium cyanamide

IV. Super phosphate

a) I and II
b) I and III
c) I, II and III
d) All
285)0.216 g of an organic compound gave 28.8 of moist nitrogen measured at 288 K and 732.7 mm pressure. The percentage of nitrogen in the substance is approximately (Aq. tension at 288 K = 12.7 mm)
a) 15
b) 20
c) 25
d) 30

286)0.10 g of an organic compound containing phosphorus gave 0.222 g of . Then the percentage of phosphorus in it is
a) 62
b) 6.2
c) 31
d) 13

287)The empirical formula of a compound represents the
a) Actual number of atoms of the various elements
b) Simplest ratio of atoms
c) Types of bonds between different atoms
d) Arrangement of various atoms in the molecule

288)The empirical formula weight is calculated by
a) Adding the atomic weights of all the atoms present in the empirical formula
b) By dividing the molecular weight by two
c) By multiplying the vapour density by two
d) By multiplying the equivalent weight by valency

289)The molecular formula of a compound represents the
a) Simplest ratio of atoms of the various atoms present in one molecule
b) Actual number of atoms of the various atoms present in one molecule
c) Type of bonds present between different atoms
d) Arrangement of various atoms within the molecule

290)An organic compound with carbon = 40 % and hydrogen = 6.6 % will have an empirical formula

291)32 g of an organic compound contains 12g carbon, 4g hydrogen and the rest oxygen. Its empirical formula is

292)An organic compound contains 10 % C, 0.84 % H and 89.2 % Cl. Its empirical formula is

293)An organic compound contains 29.27 % carbon, 5.69 % hydrogen and 65.04 % bromine. Its empirical formula is

294)The empirical formula of a compound containing 50 % of element X (At. wt. 10) and 50 % of element Y (At. wt. 20) is
a) XY

295)The empirical formula of a compound is and its molecular weight is 60. The compound could be

296)A compound with empirical formula has a vapour density of 90. Its molecular formula is

297)The empirical formula of a compound containing six atoms of oxygen is. Its molecular formula should be

298)The empirical formula of a compound is . The mass of one mole of the compound is 42 g. Therefore, its structural formula could be

299)The silver salt of a monobasic acid on ignition gave 60 % of Ag. The molecular weight of the acid is
a) 37
b) 33
c) 73
d) 77

300)The chloroplatinate of an organic base contains 39 % of Pt. The equivalent weight of the base is
a) 73
b) 59
c) 65
d) 45

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