Tiêu đề Basic Concepts of Chemistry.pdf ✅

CHEMISTRY Q.1 Which has maximum no. of equivalent Per mole of the oxidants - (A) Zn(S) + Vo2+(aq) → Zn2+ + V3+ (B) Ag(s) + No3 – (aq) → Ag+ (aq) + NO2(g) (C) Mg(s) + Vo4 3– (aq) → Mg2+(aq) + V2+(aq) (D) I(aq)– + Io3 – (aq) → I3 – (aq) [D] Q. 2 Which of the substance has maximum number of hydrogen atoms per gm of the substance ? At. wts. : Cu – 63.5 ; S – 32 ; O –16 ; H –1 (A) CH4 (B) CuSO4 . 5H2O (C) H2O2 (D) H2O [A] Q. 3 In a hydrocarbon, there is 3gm of carbon per gm of hydrogen present in the molecule. Therefore, molecular formula of the hydrocarbon is- (A) CH4 (B) C2H6 (C) C3H8 (D) C4H10 [A] Q. 4 NaOH can be prepared by two methods each of the method has two steps having 100% yield. Method I : 2Na + 2H2O → 2NaOH + H2 2H2 + O2 → 2H2O Method II : 2Na + 2 1 O2 → Na2O Na2O + H2O → 2NaOH Which of the above method gives better yield of NaOH ? (A) Method I (B) Method II (C) Method I & Method II give equal yields. (D) Yield cannot be determined [C] Q. 5 When 100 gm of C2H4 is polymerised to produce polyethylene according to the equation nC2H4 → (C2H4)n Then, how many gm polyethylene (C2H4)n would be produced ? At. wt : C–12 ; H – 1 (A) 100 gm (B) 100n gm (C) 2 100n gm (D) n 28 100  gm. [A] Q.6 If 0.5 moles of BaCl2 is mixed with 0.2 moles of Na3PO4, the maximum number of moles of Ba3(PO4)2 that can be formed is - (A) 0.2 (B) 0.5 (C) 0.3 (D) 0.1 [D] Q.7 The number of moles of KMnO4 that will be required to react with one mole SO3 2– ion in acidic medium is - (A) 5 2 (B) 5 3 (C) 5 4 (D) 1 [A] Q. 8 1 gm of Ca was burnt in excess of oxygen and oxide so produced is dissolved in water and thereby 1L of aqueous solution was produced. What was the normality of the aqueous solution as alkali ? (At. wt. of Ca = 40) (A) 20 1 (N) (B) 10 1 (N) (C) 40 1 (N) (D) 2 1 (N) [A] Q. 9 The equivalent volume of CO2 in the following reaction is – 2NaHCO3 → Na2CO3 + H2O + CO2 (A) 22.4 L (B) 11.2 L (C) 5.6 L (D) 22 L [B] Q. 10 10 ml of a solution containing Na2CO3 and NaHCO3 is titrated by HCl using phenolphthalein and then methyl orange (added after first end point). The first and second end points were found after adding 10 ml and 15 ml of       10 N HCl respectively. The ratio of milliequivalents of Na2CO3 and NaHCO3 in the solution is - (A) 1 2 (B) 2 1 (C) 1 5 (D) 5 1 [A] Q.11 25 ml of a given H2O2 solution require 10 ml of 0.1 (M) KMnO4 for complete oxidation in the presence of acid. What is the volume strength of H2O2 solution ? (A) 11.2 volume (B) 5.6 volume (C) 0.56 volume (D) 1.12 volume [D]
Q.12 8.4 g MgCO3 on heating leaves behind a residue weighing 4.0 g carbon dioxide released into the atmosphere at S.T.P. will be - (A) 2.24 L (B) 4.48 L (C) 1.12 L (D) 0.56 L [A] Sol. MgCO3 → MgO + CO2. Thus 84 g MgCO3 give 22.4 L CO2 at S.T.P. Hence 8.4g will give 2.24 L CO2 at S.T.P. Q.13 12 g carbon combines with 64 g sulphur to form CS2. 12 g carbon also combines with 32 g oxygen to form CO2. 10 g sulphur combines with 10 g oxygen to form SO2. These data illustrate the - (A) Law of multiple proportions (B) Law of definite proportions (C) Law of reciprocal proportions (D) Law of gaseous volumes. [C] Sol. Ratio of the weights of S and O combining with fixed weight of C is 64 : 32 = 2 : 1. Ratio of the weights of S and O combining directly = 10 : 10 = 1 : 1. The two ratios are simple multiple of each other. This proves law of reciprocal proportions. C S O (12 g) 64 g 32 g (10 g) (10 g) Q.14 2.4g of pure Mg (at. mass = 24) is dropped in 100 mL of 1M HCl. Which of the following statement is wrong ? (A) 1.12 L of hydrogen is produced at S.T.P. (B) 0.01 mol of magnesium is left behind (C) HCl is the limiting reagent. (D) None of these [A] Sol. 800 g of solution has X = 320 g Solvent in solution = 800 – 320 = 480 g X left after cooling = 320 – 100 = 220 g Total weight of solution = 480 + 220 = 700 g 700 Q.15 In the reaction 3 Cu + 8 HNO3 → 3 Cu(NO3)2 + 2NO + 4 H2O what is the equivalent weight of HNO3? if molecular weight of HNO3 is M - (A) M (B) 3 M (C) M 4 3 (D) M 3 4 [D] Sol. NO3 – → NO N+5 → N+2 change = 3 N+5 → 2 × N+2 total change = 6 n factor of per mole HNO3 = 8 6 = 4 3 Q.16 5 moles of A, 6 moles of Z and mixed with sufficient amount of C to produce final product F. How many maximum moles of ‘F’ can be produced as per the given sequence of reaction ? A + 2Z → B ; B + C → Z + F (A) 3 (B) 2 (C) 4 (D) 5 [A] Sol. Net reaction is : A + 2Z + C → Z + F As per the given information Z is the L. R.  The no. of moles of F produced = 2 1 × 6 = 3 Q.17 A mixture of H2 and I2 (vapour) in molecular proportion 2 : 3 was heated at 440o C till the reaction H2(g) + I2 (g) 2HI (g) reached equilibrium state. Calculate the percentage of I2 converted into HI. (Kc at 440o C is 0.02 and x is small compared to unity) - (A) 10% (B) 5.77 % (C) 20% (D) 8.3 % [B] Sol. H2(g) + I2(g) 2HI(g) 2a – x 3a–x 2x (2a)(3a) (2x) 2 = 0.02  a x = 1.73 × 10–1 % of I2 reacted = 3a x × 100 = 5.77 % Q.18 At 100oC and 1 atm, if the density of liquid water is 1 g cm–3 and that of water vapour is 0.0006 g
cm–3 , then the volume occupied by water molecules in 1 litre of steam at that temperature is (A) 6 cm3 (B) 60 cm3 (C) 0.6 cm3 (D) 0.06 cm3 [C] Sol. Vol.of steam = 1 lt = 103 cm3  m = d.V  mass of 103 cm3 steam = density × volume = 3 cm 0.0006 gm × 103 cm3 = 0.6 gm actual vol. occupied by H2O molecules is equal to vol. of water of same mass  Actual vol. of H2O molecules in 6 g steam = Mass of steam/density of H2O = 0.6 g /1g /cm3 = 0.6 cm3 Q.19 The equivalent weight of K4 [Fe(CN)6] in the given reaction is - K4[Fe(CN)6] ⎯⎯→ [O] Fe3+ + NO3 – + CO2 (A) M/20 (B) M/1 (C) M/60 (D) M/61 [D] Sol. K4[Fe(CN)6] →Fe + NO3 – + CO2 +2 3+ +4 +2 +1 +3 –5 +10×6=+60 +5 -4 -5 +5 Net change in oxidn no. = + 60 + 1 = + 61 Eq. wt. = 61 M 22 May 2009 __________________________________ Q.20 10–2 moles of Fe3O4 is treated with excess of KI solution in presence of dilute H2SO4, the products are Fe2+ and I2 (g). What volume of 0.1 (M) Na2S2O3 will be needed to reduce the liberated I2 (g) ? (A) 50 ml (B) 100 ml (C) 200 ml (D) 400 ml [C] Sol. Fe3O4 x =2 Fe2+ I – x =1 I2 S2O3 2– x =1 S4O6 2– I – I x = 2 2  Fe3O4 + 2I– → Fe2+ + I2  no. of moles of I2 produced = 10–2 moles Let v ml 0.1 (M) Na2S2O3 solution is required  v × 10–4 = 2 × 10–2 or v = 200 ml.  Q.21 5 mL of N HCl, 20 mL of N/2 H2SO4 and 30 mL of N/3 HNO3 are mixed together and volume made one litre. The normality of the resulting solution is : (A) N/5 (B) N/10 (C) N/20 (D) N/40 [D] Q.22 1000 g aqueous solution of CaCO3 contains 10 g of calcium carbonate. Concentration of solution is (A) 10 ppm (B) 100 ppm (C) 1000 ppm (D) 10000 ppm [D] Q.23 1.0 g of pure calcium carbonate was found to require 50 mL of dilute HCl for complete reaction. The strength of the HCl solution is given by - (A) 4N (B) 2N (C) 0.4N (D) 0.2N [C] Q.24 The normality of 10% (weight/volume) acetic acid is - (A) 1 N (B) 10 N (C) 1.7 N (D) 0.83 N [C] Q.25 What will be the normality of a solution obtained by mixing 0.45 N and 0.60 N NaOH in the ratio 2 : 1 by volume ? (A) 0.4 N (B) 0.5 N (C) 1.05 N (D) 0.15 N [B] Q.26 The molality of 1 M solution of NaCl (specific gravity 1.0585 g/mL) is : (A) 1.0585 (B) 1.0 (C) 0.10 (D) 0.0585 [B] Q.27 The molarity of pure water is : (A) 55.6 (B) 50 (C) 100 (D) 18
[A] Q.28 To neutralise 20 mL of M/10 NaOH, the volume of M/20 HCl needed is : (A) 10 mL (B) 30 mL (C) 40 mL (D) 20 mL [C] Q.29 H3PO4 is a tribasic acid and one of its salts is NaH2PO4. What volume of 1 M NaOH should be added to 12 g NaH2PO4 (mol. wt. 120) to exactly convert it into Na3PO4 ? (A) 100 mL (B) 300 mL (C) 200 mL (D) 80 mL [C] Q.30 The amount of KMnO4 required to prepare 100 mL of 0.1 N solution in alkaline medium - (A) 1.58 g (B) 0.52 g (C) 3.16 g (D) 0.31 g [A] Q.31 How many g of NaOH will be needed to prepare 250 mL of 0.1 M solution ? (A) 1 g (B) 10 g (C) 4 g (D) 6 g [A] Q.32 What volume of 0.8 M solution contains 0.1 m mole of solute ? (A) 100 mL (B) 125 mL (C) 500 mL (D) 0.125 mL [D] Q.33 How many g of glucose be dissolved to make one litre solution of 10% glucose ? (A) 10 g (B) 180 g (C) 100 g (D) 1.8 g [C] Q.34 Molecular weight of NaCl is 58.5. A solution of NaCl containing 5.85 g NaCl per litre is : (A) 1 molar (B) 0.1 molar (C) 2 molar (D) 0.585 molar [B] Q.35 The total ionic strength (total molality of all the ions) containing 0.1 M of CuSO4 and 0.1 M of Al2(SO4) is : (A) 0.2 M (B) 0.7 M (C) 0.8 M (D) 1.2 M [B] Q.36 The number of mole of KCl in 1000 mL of 3 molar solution is: (A) 1.5 (B) 3.0 (C) 1.0 (D) 4.0 [B] Q.37 1 kg of NaOH solution contains 4 g of NaOH. The approximate concentration of the solution is : (A) 1 molar (B) 0.1 molal (C) decinormal (D) about 0.1 N [B] Q.38 Equivalent weight of bivalent metal is 32.7. Molecular weight of its chloride is: (A) 68.2 (B) 103.7 (C) 136.3 (D) 166.3 [C] Q.39 The normality of 4% (wt./vol.) NaOH is : (A) 0.1 (B) 1.0 (C) 0.05 (D) 0.01 [B] Q.40 Concentration of HCl is 10 N. 100 mL of 1 N HCl can be obtained by diluting : (A) 10 mL of conc. HCl to 100 mL (B) 20 mL of conc. HCl to 100 mL (C) 100 mL of conc. HCl to 200 mL (D) 100 mL of conc. HCl to 100 mL [B] Q.41 How much water is to be added to dilute 10 mL of 10 N HCl to make it decinormal ? (A) 990 mL (B) 1010 mL (C) 100 mL (D) 1000 mL [A] Q.42 For preparing M/10 solution of H2SO4 in one litre we need H2SO4 : (A) 9.8 g (B) 49.0 g (C) 4.8 g (D) 0.09 g [A] Q.43 Mole fraction of A in water is 0.2. The molality of A in water is : (A) 13.8 (B) 13.6 (C) 14.0 (D) 16.0 [A] Q.44 10 mL of concentrated H2SO4 (18 M) is diluted to one litre. The approximate strength of the dilute acid is : (A) 18 M (B) 180 M (C) 0.18 M (D) 1.8 M [C] Q.45 The molarity of 2N H2SO4 is : (A) 1 M (B) 2 M (C) 3 M (D) 4 M