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Some Basic Concepts of Chemistry · Question 21

NEET 2016 (Phase 2)MCQEasy📈 Topic in 50% papers+4−1
1

Suppose the elements X and Y combine to form two compounds XY2 and X3Y2. When 0.1 mole of XY2 weighs 10 g and 0.05 mole of X3Y2 weighs 9 g, the atomic weights of X and Y are

  1. 40, 30
  2. 60, 40
  3. 20, 30
  4. 30, 20

Answer

(1) 40, 30

Solution

Let the atomic weights of X and Y be x and y.

Molar mass of XY2 = 100.1 = 100 g mol-1

⇒ x + 2y = 100 ...(i)

Molar mass of X3Y2 = 90.05 = 180 g mol-1

⇒ 3x + 2y = 180 ...(ii)

Subtracting (i) from (ii): 2x = 80

⇒ x = 40 and y = 100 - 402 = 30

Answer: (1)

NEET 2016 (Phase 2)

Keep practising — Some Basic Concepts of Chemistry

2

What is the mass of the precipitate formed when 50 mL of 16.9\% solution of AgNO3 is mixed with 50 mL of 5.8\% NaCl solution ? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5)

  1. 3.5 g
  2. 7 g
  3. 14 g
  4. 28 g
AIPMT 2015
3

If Avogadro number NA, is changed from 6.022 1023 mol-1 to 6.022 1020 mol-1, this would change

  1. the mass of one mole of carbon
  2. the ratio of chemical species to each other in a balanced equation
  3. the ratio of elements to each other in a compound
  4. the definition of mass in units of grams.
AIPMT 2015
4

The number of water molecules is maximum in

  1. 1.8 gram of water
  2. 18 gram of water
  3. 18 moles of water
  4. 18 molecules of water
AIPMT 2015
5

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? (At. wt. of Mg = 24)

  1. 96
  2. 60
  3. 84
  4. 75
Out of syllabusAIPMT 2015
6

A mixture of gases contains H2 and O2 gases in the ratio of 1 : 4 (w/w). What is the molar ratio of the two gases in the mixture ?

  1. 16 : 1
  2. 2 : 1
  3. 1 : 4
  4. 4 : 1
AIPMT 2015 (Cancelled)
7

Equal masses of H2, O2 and methane have been taken in a container of volume V at temperature 27 in identical conditions. The ratio of the volumes of gases H2 : O2 : methane would be

  1. 8 : 16 : 1
  2. 16 : 8 : 1
  3. 16 : 1 : 2
  4. 8 : 1 : 2
AIPMT 2014
8

When 22.4 litres of H2(g) is mixed with 11.2 litres of Cl2(g), each at S.T.P. the moles of HCl(g) formed is equal to

  1. 1 mol of HCl(g)
  2. 2 mol of HCl(g)
  3. 0.5 mol of HCl(g)
  4. 1.5 mol of HCl(g)
AIPMT 2014
9

1.0 g of magnesium is burnt with 0.56 g O2 in a closed vessel. Which reactant is left in excess and how much ? (At. wt. Mg = 24, O = 16)

  1. Mg, 0.16 g
  2. O2, 0.16 g
  3. Mg, 0.44 g
  4. O2, 0.28 g
AIPMT 2014
10

6.02 1020 molecules of urea are present in 100 mL of its solution. The concentration of solution is

  1. 0.001 M
  2. 0.1 M
  3. 0.02 M
  4. 0.01 M
NEET 2013
11

How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO3? The concentrated acid is 70\% HNO3.

  1. 70.0 g conc. HNO3
  2. 54.0 g conc. HNO3
  3. 45.0 g conc. HNO3
  4. 90.0 g conc. HNO3
NEET 2013

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