CBSE Questions for Class 12 Engineering Chemistry Solutions Quiz 14 - MCQExams.com

A solution of ethanol in water is 10% v/ v. If the solution and pure ethanol have densities 0.9886 g/cc and 0.785 g/cc respectively. % w/w of ethanol is:
  • 7.94
  • 12.11
  • 11.22
  • 9.11
On mixing $$10 \mathrm { ml } \mathrm { CCl } _ { 4 }$$ and 10$$\mathrm { ml }$$ benzene, the total volume of solution is :
  • $$> 20 \mathrm { ml }$$
  • $$< 20 \mathrm { ml }$$
  • $$20 ml$$
  • Can't be predicted
A solution is 20% ethanol by volume is found to have a density of 0.977 g/ml. The density of ethanol is 0.789 g/ml. The mass per cent of ethanol solution is:
  • 7.89%
  • 9.77%
  • 16.15%
  • 18.72%
There are two oxides of sulphur. They contain 50% and 60% of oxygen respectively by weight. The weights of sulphur which combine with 1 gm of oxygen are in the ratio of: 
  • 1 ; 1
  • 2 : 1
  • 2 : 3
  • 3 : 2
$$18 g$$ glucosse $$\left( C _ { 6 } H _ { 12 } O _ { 6 } \right)$$ is added to 178.2 g water. The vapor pressure of water (in torr) for aqueous solution is
  • $$76.0$$
  • $$752.4$$
  • $$759.0$$
  • $$7.6$$
On a certain day, the vapour pressure is 24 mm of Hg for water vapour in air at 300 K. The saturated vapour pressure is 26.463 mm. How many moles of water vapour per liter of air would be required to saturate the air at this temperature?
  • 1.0
  • 0.01
  • 0.1
  • 0.00013
One mole of non-volatile solute is dissolved in two moles of water. The vapour pressure of the solution relative to that of water is:
  • $$\cfrac{2}{3}$$
  • $$\cfrac{1}{3}$$
  • $$\cfrac{1}{2}$$
  • $$\cfrac{3}{2}$$
Volume occupied by one molecule of water (density = 1 $$gcm^{-3}$$) is:
  • $$6.023 \times 10^{-23}\ cm^3$$
  • $$3.0 \times 10^{-23}\ cm^3$$
  • $$5.5 \times 10^{-23}\ cm^3$$
  • $$9.0 \times 10^{-23}\ cm^3$$
One mole of calcium phosphide on reacting with excess of water gives:
  • three moles of phosphine
  • one mole of phosphoric acid
  • two moles of phosphine
  • one mole of $$ P_2O_5 $$
Among the following, the substance with greater lowering of vapour pressure is
  • 0.1$$ { m }$$ urea
  • 0.1$$ { m }$$ glucose
  • 0.1$${ m }$$ sucrose
  • Equal in all cases
The mass of $$CaO$$ obtained by heating 200 kg of limestone $$ ( CaCO_3) $$ which is 95% pure is: 
  • 112 kg
  • 212 kg
  • 106.4 kg
  • 124 kg
The mass of glucose required to prepare $$50mL$$ of its $$\dfrac{M}{9}$$ aqueous solution is
  • $$4 gm$$
  • $$1 gm$$
  • $$2 gm$$
  • $$3 gm$$
The vapour pressure of acetone at $$ 20^0 C $$ is 185 torr. when 1.2 g of non-volatile substance was dissolved in 100 g of acetone at $$ 20^0 C $$, its vapour pressure was 183 torr. the molar mass (in$$g.mol^{-1}$$)of the substances is ;
  • 128
  • 488
  • 32
  • 64
A substance has 16$$\%$$ by mass of Sulphur and 4$$\%$$ by mass of Oxygen. Calculate minimum molar mass of the substance.
  • $$200$$
  • $$400$$
  • $$600$$
  • $$100$$
$$6g$$ of an organic compound containing oxygen is heated with graphite and carbon monoxide formed is quantitative with converted to $$8.8g$$ of $$CO_2$$ a reaction with $$I_2O_5.$$ The percentage of oxygen in the compound is:
  • $$33.3%$$
  • $$42.4%$$
  • $$53.3%$$
  • $$22.3%$$
Mass of one atom is $$6.66\times 10^{-23}$$  g.  It percentage in an hydride is 95.24.  Thus hydride is 
  • $$MH$$
  • $$MH_{2}$$
  • $$MH_{3}$$
  • $$MH_{4}$$
The total number of ions persent in 1 $$  \mathrm{mL}  $$ of 0.1 $$  \mathrm{M}  $$ barium nitrate$$ Ba(NO _{3} )_{2}$$  solution is:-
  • $$ 6.02 \times 10^{18} $$
  • $$ 6.02 \times 10^{19} $$
  • $$ 3.0 \times 6.02 \times 10^{19} $$
  • $$ 3.0 \times 6.02 \times 10^{18} $$
15g $$B a\left(M n O_{4}\right)_{2}  $$ sample containing inert impurity is completely reacting with 100 $$  \mathrm{ml}  $$ of 11.2V$$  \mathrm{H}_{2} \mathrm{O}_{2}  $$. What will be the $$  \%  $$ purity of $$\mathrm{Ba}\left(\mathrm{MnO}_{4}\right)_{2}  $$ in the sample?
  • 5$$ \% $$
  • 10$$ \% $$
  • 50$$ \% $$
  • None of the above
The equilibrium conc.of B starting with mixture of 1 mole of A and 1/3 mole/litre of B at 300 K is 
  • $$\~ $$4x$${ 10 }^{ -11 }$$
  • $$\~ $$2 x $${ 10 }^{ -10 }$$
  • $$\~ $$2 x $${ 10 }^{ -11 }$$
  • $$\~ $$$${ 10 }^{ -10 }$$
The vapour pressure of a solution of a non-volatile electrolyte B in solvent A is 95% of the vapour pressure of the solvent at the same temperature. If the molecular weight of the solvent is 0.3 times the molecular weight of solute, the weight ratio of the solvent and solute are:
  • 0.15
  • 5.7
  • 0.2
  • 4.0
In a blood sample iron present in hemoglobin is $$3.72  \%  $$. Find no. of ion molecules in $$2g$$ of hemoglobin.
  • $$ 4.58 \times 10^{26} $$
  • $$4 \cdot 53 \times 10^{23} $$
  • $$ 5.95 \times 10^{19} $$
  • $$ 8 \times 10^{20} $$
How much slurry obtained per hour?

1533561_de346ea2a03d473ea955d00c794a5ee2.jpg
  • $$5000 kg $$
  • $$500 kg $$
  • $$19,500 kg $$
  • $$20,000 kg $$
21.6 g of silver coin is dissolved in $${ HNO }_{ 3 }$$. When $$NaCl$$ is added to this solution, all silver is precipitated as $$AgCl$$. The weight of $$AgCl$$ is found 14.35 g then, calculate % of silver in coin.
  • 50%
  • 75%
  • 100%
  • 15%
The vapour pressure of water $${ 20 }^{ \circ  }C$$ is 17.5 mmHg. If 18 g of glucose $$\left( { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 } \right) $$ is added to 178.2 g of water at $${ 20 }^{ \circ  }C$$, the vapour pressure of the resulting solution will be
  • 17.675 mmHg
  • 15.750 mmHg
  • 16.500 mmHg
  • 17.325 mmHg
1.5 g mixture of $$SiO_{2}$$ and $$Fe_{2}O_{3}$$ on very strong heating leaves a residue weighing 1.46g.The reaction responsible for loss of weight is: 
3$$Fe_{2}O_{3} \rightarrow 2Fe_{3}O_{4}  + \cfrac{1}{2} O_{2}$$ 
What is the percentage of the mass of $$Fe_{2}O_{3}$$  in the original sample? 
  • 80%
  • 20%
  • 40%
  • 60%
The ratio of lowering of vapour pressure of 0.1M aquous solutions of $$KCl, CuSO_4$$ and $$Na_2SO_4$$ is:
  • $$1:2:3$$
  • $$2:2:3$$
  • $$1:1:1$$
  • $$3:2:1$$
If the maximum concentration of $$PbCl_2$$ in water is $$0.01\ M$$ at $$298\ K$$. It's maximum concentration in $$0.1\ M$$ $$NaCl$$ will be:
  • $$2.2\times 10^{-3}\ M$$
  • $$1.8\times 10^{-4}\ M$$
  • $$1.6\times 10^{-2}\ M$$
  • $$4\times 10^{-4}\ M$$
What is the charge of $$96$$ amu of $$S ^ { 2- }$$ ?
  • $$2C$$
  • $$3.2 \times 10 ^ { - 19 } \mathrm { C }$$
  • $$9.6 \times 10 ^ { - 19 } \mathrm { C }$$
  • $$6 C$$
The mass of sulphuric acid present in grams in 100 ml of a 15% w/w solution of sulphuric acid in water (density of solution  =1.10 g/m) is:
  • 15
  • 16.5
  • 11.1
  • 33.3
60 ml of mixture of $${ NH }_{ 3 }$$ and $${ H }_{ 2 }$$ are decomposed to yield $${ N }_{ 2 }$$ and $${ H }_{ 2 }$$ and to the resulting mixture 40 ml $${ O }_{ 2 }$$ is added an the mixture is sparked to yield $${ H }_{ 2 }O.$$ When the resulting mixture of gases were passed through alkaline pyragallol 6 ml contraction was observed. Calculate the percentage composition of $$NH_3$$ in the original mixture. 
  • 85%
  • 27%
  • 68%
  • 48%
A 5% solution by mass of cane sugar in water has freezing point of 271 K and freezing point of pure water is 273.15 K.The freezing point of a 5% solution (by mass) of glucose in water is:
  • $$217.15$$ K
  • $$273.15$$ K
  • $$269.06$$ K
  • $$277.23$$ K
A certain sample of coal contains 1% sulphur by weight . what is the weight of sulphur dioxide produced when $$ 2 \times 10^6 $$ kg of this coal is brunt?
  • $$ 2 \times 10^4 Kg $$
  • $$ 4 \times 10^4 Kg $$
  • $$ 4 \times 10^5 Kg $$
  • $$ 2 \times 10^5 Kg $$
Specific volume of cylindrical virus particle is $$ 6.02 \times 10^{-2} \mathrm{cc/gm} $$ whose radius and length are $$7\mathring A$$ and $$10\mathring A$$  respectively. If $$  N_{A}=6.02 \times 10^{23} $$, find molecular weight of virus.
  • 15.4 kg/mol
  • $$ 1.54 \times 10^{4} $$ kg/mol
  • $$ 3.08 \times 10^{4} $$ kg/mol
  • $$ 3.08 \times 10^{3} $$ kg/mol
When $$CuSO_4$$ is added to a solution of ammonia: 
  • Freezing point is lowered
  • Freezing point is raised
  • Boiling point is raised
  • Both (1) $ (3)
Which one of the following has greater active mass 
  • 200 gm of lime stone in 2 lit vessel
  • 90 gm of $$\mathrm { CS } _ { 2 }$$ liquid in 100 ml vessel
  • 56 gm of $$\mathrm { N } _ { 2 }$$ gas in 0.5 lit vessel
  • 1 mole $$\mathrm { O } _ { 2 }$$ gas at STP
The number of atoms in 7.4 moles of $$Fe$$ are:
  • $$44.4 \times 10 ^ { 23 }$$
  • $$22.2 \times 10 ^ { 23 }$$
  • $$44 \times 10 ^ { 23 }$$
  • None of these
The eq. wt. of $$ Na_2S_2O_3 $$ as reductant in the reaction, 

$$ Na_2S_2O_3 +H_2O +Cl_2 \rightarrow Na_2SO_4 +2HCl + S $$ is:
  • ( Mol.wt. )/1
  • ( Mol.wt. )/2
  • ( Mol.wt. )/6
  • ( Mol.wt. )/8
In an oxidation-reduction reaction, $$MnO_4^-$$ ion is converted to $${ Mn }^{ +2 }$$ is the number equivalents of $${ KMnO }_{ 4 }$$ (mol. wt = 158) present in 250 ml of 0.04 M $${ KMnO }_{ 4 }$$ solution?
  • 0.02
  • 0.05
  • 0.04
  • 0.07
A certain compound contains only Carbon and Oxygen. Analysis show that there is $$36$$% carbon and the rest is oxygen in the compound. If its molecular mass is 400, then what is the molecular formula of the compound? [atomic weight of (C)=12 and oxygen(O)=16.]
  • $$C_{12}O_{16}$$
  • $$C_{12}O_{14}$$
  • $$C_{10}O_{16}$$
  • $$C_{11}O_{16}$$
20 mL of HC1 solution requires 29.85 ml.of 0.01M NaOH solution for complete neutralization.
  • 0.0099
  • 0.099
  • 0.99
  • 9.9
Find the number of gram molecules of hydrogen present in 1 gram molecule of methane gas .
  • 1
  • 2
  • 4
  • 8
The vapour pressure of 3 aqueous solutions $$S_{1}, S_{2}$$ and $$ S_{3}$$ of the same solute at different concentrations are plotted against temperature in Kelvin. The order of their concentrations is:
1538779_93a24e4fc15f44d2820f7718b25c6b83.JPG
  • $$S_{1} = S_{2} = S_{3}$$
  • $$S_{1} < S_{2} < S_{3}$$
  • $$S_{3} < S_{2} < S_{1}$$
  • $$S_{1} < S_{3} < S_{2}$$
The volume of water added to $$500 \mathrm { ml } , 0.5 \mathrm { M }$$ $$\mathrm { NaOH }$$ so that its strength becomes 10$$\mathrm { mg } \mathrm \ { NaOH }$$ per $$\mathrm { ml } .$$
  • $$100 \mathrm { ml }$$
  • $$200 \mathrm { ml }$$
  • $$250 \mathrm { ml }$$
  • $$500 \mathrm { ml }$$
The vapour pressure of benzene at a certain temperature is 640 mm of Hg. A nonvolatile electrolyte solute weighing 2.175 g is added to 30.08 g of benzene. If the vapour pressure of the solution is 600 mm of Hg, what is the molecular weight of the solid substance?
  • $$79.82\ u$$
  • $$84.46\ u$$
  • $$59.60\ u$$
  • $$49.50\ u$$
$$1.0   \mathrm{g}  $$ of magnesium is burnt with $$0.56   \mathrm{g}  $$ of oxygen in a closed vessel. Which reactant is left in excess and how much? 
(At. weight of $$  \mathrm{Mg}=24, \mathrm{O}=16 )  $$
  • $$Mg$$, $$0.16 g $$
  • $$ O_{2}$$, $$0.16 g $$
  • $$ \mathrm{Mg}, 0.44 \mathrm{g} $$
  • $$ O_{2}$$, $$0.28 g $$
Two liquids A and B forms an ideal solution at temperature T . When the total vapour pressure above the solution is 400 torr, the mole fraction of A in the vapour phase is 0.40 and in the liquid phase 0.The vapour pressure of pure A and B respectively are:
  • 165.54 torr, 772.00 torr
  • 240.24 torr, 840.00 torr
  • 213.33 torr, 960.00 torr
  • 312.15 torr, 865.00 torr
The solution having the highest vapour pressure is:
(assume 100% ionisation of electrolytes) 
  • $$1N\ KNO_3 $$
  • $$1N\ Ba(NO_3)_2 $$
  • $$1N\  Al_2(SO_4)_3 $$
  • $$1N\  Th(NO_3)_4 $$
Oleum is composed of $$  \mathrm{H}_{2} \mathrm{SO}_{4}  $$ and which constituent?
  • $$
    S O_{2}
    $$
  • $$
    S O_{3}
    $$
  • $$
    H_{2} S
    $$
  • $$
    \mathrm{HSO}_{4}^{(-)}
    $$
In Dumas' method of estimation of nitrogen 0.35 g of an organic compound gave 55 mL of nitrogen collected at 300 K and 715 mm pressure. The percentage composition of nitrogen in the compound would be:
(Aqueous tension at 300 K = 15 mm)
  • 14.45%
  • 15.45%
  • 16.45%
  • 17.45%
A gaseous mixture of $$He$$ and $${{\text{O}}_2}$$ is found to have a density of $${\text{0}}{\text{.543}}\;{\text{d}}{{\text{m}}^{ - 3\;}}{\text{at}}\;{\text{2}}{{\text{7}}^{\text{o}}}{\text{C}}$$ and 760 torr. The percent of mass of helium in the mixture is:
  • 66.5
  • 33.5
  • 19.75
  • 80.12
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