Free NEET Chemistry multiple-choice questions on Van't Hoff Factor. Attempt each question and reveal the answer with a full explanation.
The Van't Hoff factor ( i ) for a 0.1 ,M Al 2(SO 4) 3 solution, assuming 100 % dissociation, is: 5 3 2 4 What is the normality of a 0.3 M phosphoric acid ( H 3PO 4 ) solution when it is completely neutralized by NaOH to form Na 3PO 4 ? 0.9 N 0.3 N 0.6 N 0.1 N If the osmotic pressure of a 0.1 ,M glucose solution is , the osmotic pressure of a 0.1 ,M MgCl 2 solution at the same temperature (assuming 100 % ionization) would be: 3 2 1.5 0.5 molal aqueous solution of a weak acid (HX) is 20% ionised. If K f for water is 1.86 K kg mol -1 ,the lowering in freezing point of the solution is 0.56 K 1.12 K – 0.56 K – 1.12 K Of the following 0.10 m aqueous solutions, which one will exhibit the largest freezing point depression? KCl C6H12O6 Al2(SO4)3 K2SO4 Which of the following 0.1 M aqueous solutions will have the lowest freezing point? Al 2(SO 4) 3 K 2SO 4 KCl C 6H 12 O 6 (Glucose) The Van't Hoff factor ( i ) for a compound which undergoes dissociation in one solvent and association in another solvent is respectively: > 1 and < 1 < 1 and > 1 > 1 and > 1 < 1 and < 1 At 25 C , the highest osmotic pressure is exhibited by 0.1 M solution of: CaCl 2 KCl Glucose Urea What is the relation between the degree of dissociation ( ) and Van't Hoff factor ( i ) for an electrolyte of type A x B y ? = (i - 1) / (x + y - 1) = (i - 1) / (x + y) i = 1 + (x + y) = (i + 1) / (n - 1) Consider the following systems: (I) 0.1 M glucose, (II) 0.1 M NaCl , (III) 0.1 M BaCl 2 , (IV) 0.1 M AlCl 3 . The correct order of their osmotic pressure is: I < II < III < IV IV < III < II < I I = II = III = IV II < I < III < IV The freezing point of a 0.01 m aqueous solution of a non-electrolyte is -0.0186 C . What is the freezing point of a 0.01 m solution of NaCl in water? (Assume NaCl is 100 % ionized) -0.0372 C -0.0186 C -0.0558 C 0.0372 C The Van't Hoff factor i for a compound which undergoes dimerization in benzene is: 0.5 1.0 2.0 0 Which of the following 0.1 M aqueous solutions will have the highest freezing point? Glucose NaCl K 2SO 4 FeCl 3 The molar mass of a solute determined by colligative properties is less than the actual molar mass when: The solute undergoes dissociation The solute undergoes association The solute is non-volatile The solution is ideal A 0.0020 m aqueous solution of an ionic compound [Co(NH 3) 5(NO 2)]Cl freezes at -0.00732 C . Number of moles of ions which 1 mol of ionic compound produces on being dissolved in water will be ( K f = 1.86 C/m ): 2 3 4 1 Which of the following 0.05 ,M aqueous solutions is isotonic with a 0.10 ,M glucose solution? NaCl CaCl 2 AlCl 3 Na 3PO 4 The Van't Hoff factor ( i ) for a compound K 3[Fe(CN) 6] which is 50 % dissociated in aqueous solution is: 2.5 3.0 4.0 1.5 When benzoic acid is dissolved in benzene, it undergoes dimerization. If the observed molar mass is 244 ,g/mol (Theoretical molar mass = 122 ,g/mol ), the Van't Hoff factor i is: 0.5 2.0 1.0 0.25 Which pair of solutions will have the same osmotic pressure at the same temperature? 0.1 ,M ,NaCl and 0.1 ,M ,Na 2SO 4 0.1 ,M ,NaCl and 0.2 ,M ,Glucose 0.2 ,M ,BaCl 2 and 0.2 ,M ,Na 2SO 4 0.1 ,M ,Urea and 0.1 ,M ,NaCl If the Van't Hoff factor for a 0.1 ,M Ba(NO 3) 2 solution is 2.74 , the degree of dissociation is: 87 % 74 % 91 % 100 % The Van't Hoff factor i for a dilute solution of K 2[HgI 4] is (assuming 100 % dissociation): 3 2 4 5 The Van't Hoff factor ( i ) for a dilute solution of Al 2(SO 4) 3 assuming 80 % dissociation is: 4.2 5.0 3.4 4.0 The Van't Hoff factor ( i ) for a dilute aqueous solution of the strong electrolyte Potassium ferrocyanide K 4[Fe(CN) 6] is: 5 4 3 2 The ratio of the freezing point depression for a 0.1 ,m aqueous MgCl 2 solution to a 0.1 ,m aqueous Urea solution is approximately: 3 2 1 4 Which equation correctly incorporates the Van't Hoff factor into the relative lowering of vapour pressure formula? (P o - P) / P o = i X 2 (P o - P) / P o = X 2 / i (P o - P) / P = i X 2 (P o - P) / P o = i + X 2 The relationship between Van't Hoff factor ( i ) and degree of dissociation ( ) for an electrolyte that produces n ions is correctly represented by: = (i - 1) / (n - 1) = (n - 1) / (i - 1) i = ( - 1) / (n - 1) i = 1 + (n + 1) At 25 C , the osmotic pressure of a 0.1 M solution of a monobasic acid is 3.0 atm . The Van't Hoff factor i is approximately ( R = 0.0821 L atm K -1 mol -1 ): 1.23 1.00 1.50 2.00 If the degree of dissociation of Ca(NO 3) 2 in dilute aqueous solution is 70 % , the Van't Hoff factor i is: 2.4 1.7 3.0 2.1 The freezing point of 0.1 M aqueous solution of K 4[Fe(CN) 6] is expected to be about: 5 times that of 0.1 M glucose solution Same as 0.1 M glucose solution 2 times that of 0.1 M glucose solution 3 times that of 0.1 M glucose solution A solution of CaCl 2 and a solution of glucose are isotonic. If the concentration of glucose is 0.3 M , what is the concentration of CaCl 2 assuming 100 % ionization? 0.1 M 0.3 M 0.9 M 0.6 M If the solubility of a sparingly soluble salt AB 2 is s mol/L , the osmotic pressure of its saturated solution at T Kelvin is (assume 100 % ionization): 3 sRT sRT 2 sRT 4 sRT The Van't Hoff factor for a 0.1 M Al 2(SO 4) 3 solution is 4.2 . The degree of dissociation ( ) is: 80 % 100 % 90 % 70 % The Van't Hoff factor i for a compound which undergoes dimerization in a solvent with a degree of association is: 1 - 2 1 + 1 - 2 The Van't Hoff factor ( i ) for a dilute aqueous solution of the strong electrolyte barium hydroxide is . 3 2 1 0 For which of the following electrolytes will the Van't Hoff factor be the same as that of K 3[Fe(CN) 6] (assuming 100 % dissociation)? Al 2(SO 4) 3 K 2SO 4 Al(NO 3) 3 NaCl The degree of dissociation of a weak electrolyte AX is related to its Van't Hoff factor i by the expression: = i - 1 = 1 - i = (i - 1) / 2 = i + 1 The Van't Hoff factor i for 0.1 ,m Ba(NO 3) 2 is 2.74 . The percentage dissociation of the salt is: 87% 74% 100% 91% A 0.0020 M aqueous solution of an ionic compound Co(NH3)5(NO2)Cl freezes at -0.00732 C . Number of moles of ions which 1 mole of ionic compound produces on being dissolved in water will be : (k f=1.86 C/m ) - 1 2 3 4 The freezing point of a solution containing 0.5 g of KCl (mol. wt. = 74.5) in 100 g of water is -0.24 C . The degree of dissociation of KCl is (Given K f = 1.86 K kg mol -1 ): 92% 75% 100% 50% When 20 g of naphthoic acid ( C 11 H 8O 2 ) is dissolved in 50 g of benzene ( K f = 1.72 K kg mol -1 ), a freezing point depression of 2 K is observed. The Van't Hoff factor ( i ) is: 0.5 1.0 2.0 0.8 The freezing point depression constant for water is 1.86 C m -1 . If 5.00 g Na 2SO 4 is dissolved in 45.0 g H 2O , the freezing point is changed by -3.82 C . Calculate the Van't Hoff factor for Na 2SO 4 . 2.63 3.00 2.05 1.50 A 0.001 ,molal solution of [Pt(NH 3) 4Cl 4] in water had a freezing point depression of 0.0054 C . If K f = 1.86 , the formula of the compound is: [Pt(NH 3) 4Cl 2]Cl 2 [Pt(NH 3) 4Cl 3]Cl [Pt(NH 3) 4Cl 4] [Pt(NH 3) 4]Cl 4 If the degree of association of a solute is and it forms n -mers, the Van't Hoff factor i is given by: i = 1 - (1 - 1/n) i = 1 + (n - 1) i = 1 + (1 - 1/n) i = 1 - (n - 1) Calculate the Van't Hoff factor ( i ) for Mg 3(PO 4) 2 if it is 80 % dissociated in an aqueous solution. 4.2 5.0 3.4 3.8 The values of Van't Hoff factors for KCl , NaCl and K 2SO 4 , respectively, are: 2, 2 and 3 2, 2 and 2 2, 1 and 3 1, 1 and 2 The van't Hoff factor i for a compound that undergoes 30 % association to form dimers in a solvent is: 0.85 0.70 1.30 1.15 A 0.004 ,M solution of Na 2SO 4 is isotonic with a 0.01 ,M solution of glucose. The degree of dissociation of Na 2SO 4 is: 0.75 0.5 0.85 1.0 A 5.85 % ,(w/v) solution of NaCl is isotonic with a 1.0 ,M solution of a non-electrolyte. What is the apparent degree of dissociation of NaCl ? 0.0 0.5 1.0 0.8 Which of the following 0.1 ,M aqueous solutions will have the lowest vapour pressure? Al 2(SO 4) 3 NaCl KCl Glucose The Van't Hoff factor i for a compound which is 100 % dissociated in aqueous solution and has the formula A 2B 3 is: 5 4 3 2 Which of the following aqueous solutions will exhibit the largest freezing point depression? 0.1 m Al 2(SO 4) 3 0.1 m K 2SO 4 0.1 m KCl 0.1 m Glucose Which of the following salt solutions will have the same osmotic pressure as 0.1 M NaCl solution? (Assume 100 % ionization) 0.1 M KCl 0.1 M Na2SO4 0.1 M MgCl2 0.1 M AlCl3