Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Some Basic Concepts of Chemistry question

2022 · 27 Jul · Shift 1 · Q1
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Chemistry
  4. /Some Basic Concepts of Chemistry
  5. /2022 · 27 Jul · Shift 1 · Q1

Some Basic Concepts of Chemistry question

2022 · 27 Jul · Shift 1 · Q1

JEE MainChemistrySome Basic Concepts of ChemistryMCQ+4 / −1
250 g250 \mathrm{~g}250 g solution of D\mathrm{D}D-glucose in water contains 10.8%10.8 \%10.8% of carbon by weight. The molality of the solution is nearest to (Given: Atomic Weights are, H,1 u;C,12 u;O,16 u\mathrm{H}, 1 \,\mathrm{u} ; \mathrm{C}, 12 \,\mathrm{u} ; \mathrm{O}, 16 \,\mathrm{u}H,1u;C,12u;O,16u)
  1. A
    1.03
  2. B
    2.06
  3. C
    3.09
  4. D
    5.40
View written solutionFree

Correct answer: B

  1. Formula and molar mass of D-glucose

D-glucose has formula: C6H12O6\mathrm{C_6H_{12}O_6}C6​H12​O6​

Molar mass: 6(12)+12(1)+6(16)=72+12+96=180 g mol−16(12) + 12(1) + 6(16) = 72 + 12 + 96 = 180\ \text{g mol}^{-1}6(12)+12(1)+6(16)=72+12+96=180 g mol−1

  1. Carbon content in glucose

Mass of carbon in 111 mole of glucose: 6×12=72 g6 \times 12 = 72\ \text{g}6×12=72 g

So, mass fraction of carbon in glucose is: 72180=0.4\frac{72}{180} = 0.418072​=0.4

Thus, 40%40\%40% of glucose by mass is carbon.

  1. Carbon present in the given solution

The solution mass is 250 g250\ \text{g}250 g and it contains 10.8%10.8\%10.8% carbon by weight.

So, mass of carbon in solution is: 10.8100×250=27 g\frac{10.8}{100} \times 250 = 27\ \text{g}10010.8​×250=27 g

  1. Mass of glucose in the solution

Since glucose is 40%40\%40% carbon by mass, 0.4×(mass of glucose)=270.4 \times (\text{mass of glucose}) = 270.4×(mass of glucose)=27

Therefore, mass of glucose=270.4=67.5 g\text{mass of glucose} = \frac{27}{0.4} = 67.5\ \text{g}mass of glucose=0.427​=67.5 g

  1. Mass of solvent (water)

Total solution mass = 250 g250\ \text{g}250 g

So, mass of water: 250−67.5=182.5 g=0.1825 kg250 - 67.5 = 182.5\ \text{g} = 0.1825\ \text{kg}250−67.5=182.5 g=0.1825 kg

  1. Moles of glucose

n=67.5180=0.375 moln = \frac{67.5}{180} = 0.375\ \text{mol}n=18067.5​=0.375 mol

  1. Molality

Molality is: m=moles of solutekg of solvent=0.3750.1825m = \frac{\text{moles of solute}}{\text{kg of solvent}} = \frac{0.375}{0.1825}m=kg of solventmoles of solute​=0.18250.375​

m≈2.055≈2.06m \approx 2.055 \approx 2.06m≈2.055≈2.06

  1. Match with options

Nearest value is: 2.06\boxed{2.06}2.06​ So, the correct option is B.

PreviousNext

More from Some Basic Concepts of Chemistry

  • In Carius method of estimation of halogen, 0.45 g of an organic compound gave 0.36 g of AgBr. Find out the percentage of bromine in the compound. (Molar masses : AgBr=188 g mol−1;Br=80 g mol−1…2022 · MCQ
  • 20 mL of 0.02MK2​Cr2​O7​ solution is used for the titration of 10 mL of Fe2+ solution in the acidic medium. The molarity of Fe2+…2022 · Numerical
  • Two elements A and B which form 0.15 moles of A2​B and AB3​ type compounds. If both A2​B and AB3​ weigh equally, then the atomic weight of A is ​ times of atomic weight of B.2022 · Numerical
  • 116 g of a substance upon dissociation reaction, yields 7.5 g of hydrogen, 60 g of oxygen and 48.5 g of carbon. Given that the atomic masses of H, O and C are 1, 16 and 12, respectively. The data agrees with how many formulae of the…2022 · Numerical
  • In the given reaction, X+Y+3Z⇆XYZ3​ if one mole of each of X and Y with 0.05 mol of Z gives compound XYZ3​. (Given : Atomic masses of X,Y and Z are 10, 20 and 30 amu, respectively.) The…2022 · Numerical
  • On complete combustion of 0.492 g of an organic compound containing C,H and O, 0.7938 g of CO2​ and 0.4428 g of H2​O was produced. The…2022 · Numerical
  • 2L of 0.2M H2​SO4​ is reacted with 2L of 0.1M NaOH solution, the molarity of the resulting product Na2​SO4​ in the solution is ​ millimolar. (Nearest integer)2022 · Numerical
  • Compound A contains 8.7% Hydrogen, 74% Carbon and 17.3% Nitrogen. The molecular formula of the compound is, Given : Atomic masses of C, H and N are 12, 1 and 14 amu respectively. The molar mass of the compound A is 162 g mol − 1.2022 · MCQ