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

3g of a metal M combines with 2g of oxygen to form its metal oxide. 0.03 equivalent of this metal oxide is dissolved in 500ml of water to form 0.01 molar aqueous solution. Molar mass of metal oxide is (assuming no change in volume of solution)
  • 180g
  • 160g
  • 140g
  • 120g
There are two common oxides of Sulphur, one of which contains 50% O2 by weight, the other almost exactly 60%. The weights of sulphur which combine with 1g of O2 (Fixed) are in the ratio of:
  • 1:1
  • 2:1
  • 2:3
  • 3:2
Iron forms two oxides, in first oxide 56 grams of Iron is found to be combined with 16 gram oxygen and in second oxide 112 gram of Iron is found to be combined with 48 gram oxygen. This data satisfy the law of
  • Conservation of mass
  • Reciprocal proportion
  • Multiple proportions
  • Combining volume
What is the correct order of occurance (% by weight) in air of Ne, Ar and Kr ?
  • Ne > Ar > Kr
  • Ar > Ne > Kr
  • Ar > Kr > Ne
  • Ne > Kr > Ar.
1 mole of oxygen gas weighs ______________
  • 3g
  • 32g
  • 1g
  • 6.022×1022
Mole fraction of glycerine (C3H5(OH)3) in a solution of 36 g of water and 46 g of glycerine is :
  • 0.46
  • 0.36
  • 0.20
  • 0.40
The density of gas is 0.0002136 g/mL.  Its vapour density is :- 
  • 12
  • 24
  • 48
  • 32
At 25oC the density of 15MH2SO4is1.8gcm3. Thus, mass percentage of H2SO4 is aqueous solution is 
  • 2%
  • 81.6%
  • 18%
  • 1.8%
All homologues of which of the following hydrocarbons have the same percentage composition 
  • Alkanes
  • Alkynes
  • Alkenes
  • Alkadienes
The fractional abundance of Cl35 in a sample of chlorine containing only Cl35 (atomic weight =34.9) and Cl37 (atomic weight =36.9) isotopes, is 0.6. The average mass number of chlorine is  _______________.
  • 35.7
  • 35.8
  • 18.8
  • 35.77
In which of the following sets all the compounds are ionic?
  • BCl3,BeCl2,MgO
  • LiF,MgCl2,Na2O
  • NH4Cl,BF3,CO2
  • AgCl,AlCl3,PCl5
An element X have three isotopes X20,X21 and X22. The percentage abundance of X20 is 90% and the average atomic mass of element is 20.18. The percentage abundance of X21 should be ______________.
  • 2%
  • 8%
  • 10%
  • 0%
1.0 g of Mg is burnt with 0.28 g of O2 in a closed vessel. Which reactant is left in excess and how much?
  • Mg,5.8 g
  • Mg,0.58 g
  • O2,0.24 g
  • O2,2.4 g
Percentage of oxygen in urea is about :
  • 20.24 %
  • 26.64 %
  • 46.19 %
  • 7.86 %
A sample of clay contains 50\% silica and 10\% water. The sample is partially dried by which it loses 8\ g water. If the percentage of silica in the partially dried clay is 52, what is the percentage of water in the partially dried clay?
  • 2.0\%
  • 6.4\%
  • 10.4\%
  • 2.4\%
Compound Q contains 40\% carbon by mass.
What could Q be?
1. glucose, C_6H_{12}O_6
2. starch, (C_6H_{10}O_5)_n
3. sucrose, C_{12}H_{22}O_{11}.
  • 1, 2 and 3 are correct
  • 1 and 2 only are correct
  • 2 and 3 only are correct
  • 1 only is correct
Solid ammonium dichromate decomposes as under:
( NH_4)_2Cr_2O_7 \rightarrow N_2 + Cr_2O_3 +4H_2O if 63 g of ammonium dichromate decomposes, calculate the volume of N_2 evolved at STP.
  • 11.2 L
  • 5.6 L
  • 22.4 L
  • 1 L
  • 44.8 L
A quantity of 13.5\ g of aluminium when change to Al^{3+} ion in solution, will lose (Al=27).
  • 18.0\times 10^{23} electrons
  • 6.02\times 10^{23} electrons
  • 3.01\times 10^{23} electrons
  • 9.0\times 10^{23} electrons
A certain mixture of MnO and MNO_2 contains 66.6\ mol per cent of MnO_2. What is the approximate mass percent of Mn in it? (Mn=55)  
  • 66.67
  • 24.02
  • 72.05
  • 69.62
The mass composition of universe may be given as 90\%\ H_2 and 10\%\ He. The average molecular mass of universe should be ____________.
  • 2.20
  • 2.10
  • 3.80
  • 3.64
From \ 2 \ mg calcium 1.2\times 10^{19} atoms are removed. The number of g - atoms of calcium left is (Ca=40):
  • 5\times 10^{-5}
  • 2\times 10^{-5}
  • 3\times 10^{-5}
  • 5\times 10^{-6}
In the atomic weight determination. Dalton suggest the formula of water as HO and the composition of water as hydrogen =12.5\% and oxygen =87.5\% by weight. What should be the atomic weight of oxygen on H-scale, on the basis of this information?
  • 16
  • 8
  • 14
  • 7
Dopamine is neurotransmitter, a molecular that serves to transmit message in the brain. The chemical formula of dopamine is C_{8}H_{11}O_{2}N. How many moles are there in 1\ g of dopamine?
  • 0.00654
  • 153
  • 0.0654
  • None\ of\ these
A sample of impure cuprous oxide contains 66.67\% copper, by ,mass. What is the percentage of pure Cu_2O in the sample? (Cu=63.5) 
  • 66.67
  • 75
  • 70
  • 80
Molecular mass of dry air is ________________.
  • less than moist air
  • greater than moist air
  • equal to moist air
  • may be greater or less than moist air
When 2.5\,g of a sample of Mohr's salt reacts completely with 50\,mL of \dfrac{N}{10} KMnO_4 solution. The % purity of the sample of Mohr's salt is:
  • 78.4
  • 70
  • 37
  • 40

The composition of a sample of wustite is  Fe_{0.95} O_{1.00}. What is the percentage of  Fe(III) in the sample?

  • 10.52%
  • 3.46%
  • 13.84%
  • 93.08%
A vessel contains 1 mole of O_2 gas at a temperature T. The pressure of the gas is P. An identical vessel containing 1 mole of He gas at a temperature 2T has a pressure of?
  • P/8
  • P
  • 2P
  • 8P
A mixture of He(4) and Ne(20) in a 5-litre flask at 300\ K and 1 atm weighs 4\ g. The mole \% of He is
  • 2
  • 0.02
  • 20
  • 4
What is involved in CO_2 and CH_4 inclusion?
  • Diamond inclusion
  • Fluid inclusion
  • Natural inclusion
  • Crystal inclusion
What percentage of hydrogen fluoride molecules is trimerized?
  • 40
  • 58.8
  • 76.47
  • 17.65
10 grams of a solute is dissolved in 90 grams of a solvent. Its mass percent in solution is
  • 0.01
  • 11.1
  • 10
  • 9
One of the statements of Dalton's atomic theory is given below:
Compounds are formed when atoms of different elements combine in a fixed ratio.
Which of the following laws is/are not related to this statement?
  • Law of conservation of mass
  • Law of definite proportions
  • Law of multiple proportions
  • Avogadro law
Which of the following reactions is not according to the law of conservation of mass?
  • 2Mg(s)+O_2(g)\to 2MgO(s)
  • C_3H_3(g)+O_2(g)\to CO_2(g)+H_2O(g)
  • P_4(s)+5O_2(g)\to P_4O_{10}(s)
  • CH_4(g)+2O_2(g)\to CO_2(g)+2H_2O(g)
Mass is measure of the amount of matter.
  • True
  • False
The accepted unit of atomic and molecular mass is:
  • kilogram 
  • gram 
  • pound
  • atomic mass unit

Which of the given laws of chemical combination is satisfied by the figure?
1841998_f38eefb72b494816afaab449ad11217d.png
  • Law of multiple proportion
  • Gay Lussac's law
  • Avogadro law
  • Law of definite proportion
"Equal volumes of all gases at the same temperature and pressure contain equal number of particles." This statement is a direct consequence of:
  • Avogadro's law
  • Charles law
  • Ideal gas equation
  • Law of partial pressure
40\,mL gaseous mixture of CO , CH_4 and Ne was exploded with 10\,mL of oxygen. On cooling the gases occupied 36.5\,mL . After treatment with KOH the volume reduced by 9\,mL again on treatment with alkaline pyrogallol, the volume further reduced. 
Percentage of CH_{4} in the original mixture is:
  • 22.5
  • 77.5
  • 7.5
  • 15
How many molecules are there in one mole of a compound?
  • 60.22\times 10^{-23}
  • 6.022\times 10^{-23}
  • 60.22\times 10^{23}
  • 6.022\times 10^{23}
4 mole of a mixture of Mohr's salt and Fe_2(SO_4)_3 requires 500\,mL of 1\,M \,K_2Cr_2O_7 for complete oxidation in acidic medium. The mole % of the Mohr's salt in the mixture is:
  • 25
  • 50
  • 60
  • 75
The weight percentage of NaCl solution isIf the weight of the solution is 150 gms, then calculate the weight of Na and water in gms.
  • 15,135
  • 25,125
  • 50,100
  • 75,75
5 g of crystalline salt, when rendered anhydrous, lost 1.89 g of water. The formula weight of anhydrous salts is 160. The number of molecules of water of crystallisation in the salt is:
  • 1
  • 2
  • 3
  • 5
Na_2SO_xH_2O has 50% H_2O by mass. Hence, x is:
  • 4
  • 45
  • 6
  • 7
Given that the abundances of isotopes ^{54}Fe, ^{56}Fe and ^{57}Fe are 5\%, 90\% and 5\% respectively, the atomic mass of Fe is:
  • 55.85
  • 55.95
  • 55.75
  • 56.05
In a gaseous mixture, if an alkane (C_xH_{2x+ 2}) and an alkene (C_yH_{2y}) are taken in 2 : 1 mole ratio, the average molecular weight of the mixture is observed to be 20. If the same alkane and alkene are taken in 1 : 2 mole ratio, the average molecular weight of the mixture is observed to be 24. Then, the value of x and y are respectively :
  • 2, 1
  • 1, 2
  • 2, 3
  • 3, 2
In what ratio should a 15% solution of acetic acid be mixed with a 3% solution of the acid to prepare a 10% solution?

[All percentages are mass/mass percentages.]
  • 7:3
  • 5:7
  • 7:5
  • 7:10
Cu_{2}S and M_{2}S are isomorphous in which percentage of sulphur is 20.14% and 12.94% respectively. The atomic weight of M is: 

[Atomic wt. of Cu = 63.5]
  • 208
  • 108
  • 112
  • 106
A 1.24 M aqueous solution of KI has density of 1.15 g / cm^{3} . What is the percentage composition of solute in the solution?
  • 17.89
  • 27.89
  • 37.89
  • 47.89
4.9 g sample of KClO_{3} was heated under such conditions that a part of it decomposed according to the equation: 2KClO_{3}\rightarrow 2KCl+3O_{2} and remaining underwent change according to the equation: 4KClO_{3}\rightarrow 3KClO_{4}+KCl. If the amount of O_{2} evolved was 672 mL at 1 atm and 273 K, the percentage by weight of KClO_{4} in the residue is :
  • 52.72 \%
  • 46.64\%
  • 54.86\%
  • 42.35\%
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