# CBSE Questions for Class 11 Medical Chemistry Some Basic Concepts Of Chemistry Quiz 14 - MCQExams.com

 $$60$$g of solution containing $$40\%$$ by mass of NaCl are mixed with $$100$$g of a solution containing $$15\%$$ by mass NaCl. Determine the mass percent of sodium chloride in the final solution.
• $$24.4\%$$
• $$78\%$$
• $$48.8\%$$
• $$19.68\%$$
 An organic compound contains 69% carbon and 4.8% hydrogen, the remainder being oxygen. What will be the masses of the carbon dioxide and water produces when 0.20g of this substance is subjected to the complete combustion?
• 0.69 g and 0.048g
• 0.506 g and 0.086g
• 0.345 g and 0.0024 g
• 0.91 g and 0.72 g
 If a solution contains 34.2 g of sugar in 100 g of water. Find the concentration inn terms of mass by mass percentage of the solution?
• 20 %
• 25.48 %
• 50 %
• 10 %
 A mixture of $$NaHCO_3$$  and $$Na_2CO_3$$ weighs 950 gm. When the mixture is heated strongly in an open vessel, till constant weight, the mass of sample reduced by 155 gm. The correct information(s) is/ are ?
• The mass percent of $$NaHCO_3$$ in initial mixture = 50%
• The mole percent of $$Na_2CO_3$$ in initial mixture = 50%
• Final sample contains only $$Na_2O$$
• The loss in mass is only due to $$CO_2$$ gas evolved
 P and Q are two elements which form $${ P }_{ 2 }{ Q }_{ 3 }$$ and $${ PQ }_{ 2 }$$. If 0.15 mole of $${ P }_{ 2 }{ Q }_{ 3 }$$ weight 15.9 g and 0.15mole of $${ PQ }_{ 2 }$$ weight 9.3 g. what are atomic weights of P and Q respectively?
• 18 and 26
• 26 and 26
• 26 and 18
• 18 and 18
 What percent of a sample of nitrogen must be allowed to escape if its temperature, pressure, and volume are to be changed from $$220^oC$$, $$3$$atm and $$1.65$$litre to $$110^oC$$, $$0.7$$ atm and $$1.00$$ litre respectively?
• $$81.8$$%
• $$71.8$$%
• $$76.8$$%
• $$86.8$$%
 $$3 g$$ of activated charcoal was added to $$50 mL$$ of acetic acid solution ($$0.06 N$$) in a flask. After an hour it was filtered and the strength of the filtrate was found to be $$0.042 N$$. The amount of acetic acid absorbed (per gram of charcoal) is ?
• $$18 mg$$
• $$36 mg$$
• $$42 mg$$
• $$54 mg$$
 A substance contains 3.4%$$S$$. if it contain two atom of sulphur per molecule then minimum molecular weight of substance will be:
• 188.2
• 94.1
• 1882
• 282.3
 Find out the weight of solute (M. wt. 60) that is required to dissolve in $$180g$$ water to reduce the vapour pressure to $$\dfrac{4}{5}th$$ of pure water:
• $$120g$$
• $$150g$$
• $$300g$$
• $$75g$$
 A sample of diesel has the same knocking characteristics as a 60 ml mixture of cetane and $$a$$- methyl  naphthalene mixed in 2 :1 ratio .The cetane number of the diesel sample is :
• 60
• 40
• 66.6
• 33.3
 4.24 g of an organic compound on combustion produces 8.45 g of $${ CO }_{ 2 }$$ and 3.46 g of water. The mass percentage of $$C$$ and $$H$$ in the compound respectively are:
• $$27.2, 18.2$$
• $$54.4,9.1$$
• $$9.1,54.4$$
• $$18.2,27.2$$
 Air has three major components : nitrogen,oxygen  and argon. Given that one mole of air at sea level is made up of 78% nitrogen, 21% oxygen, and 1% argon, by volume. What is the density of air? Assume that gases behave in an ideal manner. (Atomic mass of argon is 40 amu)
• 14.62 g/L
• 1.3 g/L
• 29 g/L
• 0.65 g/L
 The volume of $$0.1\ M\ H_2SO_4$$ required to neutralize 30 mL of $$2.0\ M\ NaOH$$ is:
• 100 mL
• 300 mL
• 400 mL
• 200 mL
 When 15gm of a mixture of $$NaCl$$ and $$Na_2CO_3$$ is heated with dilute hydrochloric acid, 2.5gm of $$CO_2$$ is evolved at NTP. Calculate percentage composition of $$Na_2CO_3$$ in a mixture.
• $$59.85\%$$
• $$40.15\%$$
• $$30\%$$
• $$70\%$$
 A mixture of $${ C }_{ 2 }{ H }_{ 2 }$$ AND  $${ C }_{ 3 }{ H }_{ 8 }$$ occupied a certain volume at 80 mm Hg . The mixture wsa completely burnt to $${ CO }_{ 2 }$$ and $${ H }_{ 2 }O$$ (l). When the pressure of $${ CO }_{ 2 }$$ was found to be 230 mm Hg at the same temperature and volume, the mole fraction of $${ C }_{ 3 }{ H }_{ 8 }$$  in the mixture is
• 0.125
• 0.875
• 0.6
• 0.8
 $$\cfrac{N_{A}}{4}$$ atoms of an element ionise by absorbing $$X\ kJ$$ of energy, then the ionisation energy of the elements is: ($$N_{A}$$= Avogadro number)
• $$2X$$
• $$4X$$
• $$\cfrac{4}{X}$$
• $$\cfrac{1}{4X}$$
 Two oxide of metal contain 27.6% and 30% oxygen respectively. If the formula of first oxide is $$M_3O_4$$ then formula of second oxide is -
• $$MO$$
• $$M_2O$$
• $$M_2O_3$$
• $$MO_2$$
 $$81gm$$ mixture of $$MgC{O_3}\left( s \right)$$ $$N{H_2}COON{H_4}\left( s \right)$$ in equimolar ratio is heated in open to constant mass. If vapour density of gaseous mixture evolved was found to be $$\cfrac{61}{4}$$, then find the mole % of $$MgCO_3$$ in original sample.Given that: $$MgC{O_3}\left( s \right)\xrightarrow{\Delta }MgO\left( s \right) + C{O_2}\left( g \right)$$ $${H_2}COON{H_4}\left( s \right)\xrightarrow{\Delta }2N{H_3}\left( g \right) + C{O_2}\left( g \right)N$$
• $$50\%$$
• $$51.9\%$$
• $$70.9\%$$
• $$59.1\%$$
 In the mixture of $$(NaHCO_3 + Na_2CO_3$$) in 1:1 molar ratio, the volume of $$HCl$$ required is $$'x'$$ ml with methyl orange and $$'y'$$ ml with phenolphthalein indicator for 2 different titrations from start for equal volumes of original solution. The relation between $$x$$ and $$y$$ is:
• $$x = 3y$$
• $$y = 3x$$
• $$x =6y$$
• $$y = 6x$$
 Substance Boiling point $${ ( }^{ 0 }C)$$ Melting point $${ ( }^{ 0 }C)$$ A -183 -219 B 445 119 C 78 -15

Point out the physical states of A, B, and C at room temperature $$({ 30 }^{ 0 }C)$$.
• Gas, solid, liquid
• Gas, liquid, solid
• Liquid, solid, gas
• Solid, liquid, gas
 100 gm impure $$CaCO_3$$ on heating gives 5.6 lit. $$CO_2$$ gas at NTP. Find the percentage of calcium in $$CaCO_3$$ sample.
• 1
• 40
• 10
• 30
 If a sample of $$MgBr_2$$ contains $$4\times 10^{20} Br^-$$ ions, then the number of $$Mg^{2+}$$ ions present in it is:
• $$4 \times 10^{20}$$
• $$8 \times 10^{20}$$
• $$2 \times 10^{20}$$
• $$1 \times 10^{20}$$
 Vapour density of the equilibrium mixture of $$NO_2$$ and $$N_2O_4$$ is found to be $$40$$ for the equilibrium. Calculate percentage of $$NO_2$$ in the mixture:  $$N_2O_4 \leftrightharpoons 2 NO_2$$
• $$10$$ %
• $$5$$ %
• $$26.08$$ %
• None of these
 0.1 g of a solution containing $$Na_2CO_3$$ and $$NaHCO_3$$ requires 10 mL of 0.01 N HCl for neutralization using phenolphthalein as an indicator. Wt % of $$Na_2CO_3$$ in the mixture is
• 25
• 32
• 50
• 10.6
 $$12\ g$$ of impure cyanogen undergoes hydrolysis by two different pathways :i) $$(CN)_{2}+4H_{2}O \rightarrow (NH_{4})_{2} C_{2}O_{4}$$ii) $$(CN)_{2}+2H_{2}O \rightarrow NH_{2}CONH_{2}$$The same amount of urea was obtained when $$11.52\ g$$ of pure ammonium carbonate was heated. If $$20\ mL$$ of $$1.6\ M$$ acidic $$KMnO_{4}$$ was required to completely oxidise $$(NH_{4})_{2}C_{2}O_{4}$$ then which of the following statement is incorrect ?
• $$\%$$ purity of cyanogen is $$86.67\%.$$
• $$\%$$ purity of cyanogen is $$60.67\%.$$
• $$\%$$ progress in case $$(i)$$ is $$40\%.$$
• $$\%$$ progress in case $$(ii)$$ is $$60\%.$$
 0.1 g of a solution containing $${ Na }_{ 2 }$$$${ Co }_{ 3 }$$ and $${ NaHCO }_{ 3 }$$ requires 10 mL of 0.01 N HCl for neutralization using phenolphthalein as an indicator.Wt.% of  $${ Na }_{ 2 }$$$${ Co }_{ 3 }$$ in the mixture is
• 25
• 32
• 50
• 10.6
 What weight of $$NaHSO_3$$ is required to react with $$100mL$$ of solution containing $$0.33g$$ of $$NaIO_3$$ according to the following reaction $${IO}_{3}^{\Theta}+HS{O}_{3}^{\Theta}\longrightarrow I^{\Theta}+{SO}_{4}^{2-}$$
• $$0.52g$$
• $$5.2g$$
• $$1.04g$$
• $$10.4g$$
 Avogadro number is the number of molecule present in
• 1 lit of any gas at NTP
• 10 lit of any gas at NTP
• 11.2 lit of any gas at NTP
• 22.4 lit of any gas at NTP
 A gas cylinder of the capacity of 20 $$dm^{3}$$ is filled with gas $$X$$, the mass of which is $$10\ gm$$. When the same cylinder is filled with hydrogen gas at the same temperature and pressure the mass of the hydrogen is $$2 \ gm$$ hence the relative molecular mass of the gas is:
• 5
• 10
• 15
• 20
 The $$O^{18}/O^{16}$$ ratio in some meteorites is greater than the used to calculate the average atomic mass of oxygen one earth. The average mass of an atom of oxygen in these meteorites is ______ that of terrestrial oxygen atom?
• equal to
• greater than
• less than
• none of these
 An oxide, $$X_{2}O_{3}$$ is oxidized to $$X_{4}^{-}$$ by $$Cr_{2}O_{7}^{2-}$$ in acid medium. The number of moles of $$X_{2}O_{3}$$ oxidized per mole of $$Cr_{2}O_{7}^{2-}$$ is
• 2
• 3
• 3/2
• 2/3
 Gold crystallizes with FCC lattice for which the side length of the unit cell is $$5.0\mathring { A }$$. If the density of gold is $$10.5g/{cm}^{3}$$, the value of Avagadro number is $$(Au=198)$$
• $$6.022\times { 10 }^{ 23 }$$
• $$6.034\times { 10 }^{ 23 }$$
• $$5.966\times { 10 }^{ 23 }$$
• $$6.022\times { 10 }^{ 22 }$$
 What percentage of hydrogen fluoride molecules is dimerized?
• $$50$$
• $$58.8$$
• $$76.47$$
• $$17.65$$
 If the ratio of mole fraction of solute and solvent is unity, then the mass per cent of solute is (Molar masses of solute and solvent are $$X$$ and $$Y$$ respectively)
• $$50\%$$
• $$\dfrac{X}{X+Y}\times 100\%$$
• $$\dfrac{X}{Y}\times$$ mass per cent of solvent
• $$\dfrac{Y}{X}\times$$ mass per cent of solvent
 If in esterification, initially equal moles of alcohol and acid are taken. At equilibrium, unreacted alcohol and acid, on the treatment of sodium, produced $$H_2$$ which occupied 44.8 L at $$0^o C$$ and 1 atm. The percentage esterification of acid and alcohol is:
• 25 %
• 33.3 %
• 50 %
• 66.7 %
 A solution containing 4.2 g of KOH and $$Ca(OH)_2$$ is neutralised by an acid. If it consumes 0.1 equivalent of acid, composition of sample in solution is which of the following?
• 45%, 55%
• 35%, 65%
• 25%, 75%
• 15%, 85%
 Complete combustion of $$858.0 \,g$$ of compound $$X$$ gives $$63.2 \,g$$ of $$CO_{2}$$ and $$1.28 \,g$$ of $$H_{2}O.$$ The lowest molecular mass $$X$$ can have:
• $$43 \,g$$`
• $$86 \,g$$
• $$129 \,g$$
• $$172 \,g$$
 The correct sequence in decreasing order of the percentage of nitrogen in the given compounds is
• Urea > Ammonium chloride > Ammonium nitrate > Ammonium nitrite
• Urea > Ammonium nitrate > Ammonium nitrite > Ammonium chloride
• Urea > Ammonium nitrite > Ammonium Nitrate > Ammonium chloride
• Urea > Ammonium nitrite > Ammonium chloride > Ammonium nitrate
 Chemistry plays an important role in national economy.
• True
• False