HARD
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On subjecting 20 ml mixture of N2 and CO to repeated electric spark, 7 ml of O2 was required for combustion. What was the mole percentage of CO in the mixture under identical conditions?

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Important Questions on Some Basic Concepts of Chemistry

MEDIUM
The molecular formula of a commercial resin used for exchanging ions in water softening is C8H7SO3Na molecular weight=206. What would be the maximum uptake of Ca2+ ions by the resin if expressed in mol per gm?
EASY

The temperature of an object is 60°C. Its value in Fahrenheit scale is

MEDIUM
Let a resistor having 4 ohm resistance be connected across the terminals of a 12 volt battery. Then, the charge in coulomb passing through the resistor per second is
HARD

Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time, the passage of air is stopped, but the heating is continued in a closed furnace such that the contents undergo self-reduction. The weight (in kg) of Pb produced per kg of O2 consumed is ____. (Atomic weights in g mol-1: O=16, S=32, Pb=207)

Give the answer to the nearest integer value.

MEDIUM
The angular diameter of a planet measured from earth is 90". If the diameter of the planet is π×106 m, then its distance from the earth is
EASY
For the following reaction, the mass of water produced from 445 g  of C57H110O6 is: 2 C57H110O6s+163O2g114 CO2g+110H2Ol
MEDIUM

A gaseous hydrocarbon on combustion gives 0.72 g of water and 3.08 g CO2. What is the empirical formula of the hydrocarbon?

HARD
A certain liquid has a melting point of -50°C and a boiling point of 150°C. A thermometer is designed with this liquid and its melting and boiling points are designated at 0°L and 100°L. The melting and boiling points of water on this scale are
 
MEDIUM

The ammonia is prepared by treating ammonium sulphate with calcium hydroxide is completely used by NiCl2·6H2O to form a stable coordination compound. Assume that, both the reactions are 100% completed. If 1584 g of ammonium sulphate and 952 g of NiCl2·6H2O are used in the preparation, the combined weight (in grams) of gypsum and the nickel ammonia coordination compound produced is ____.

Atomic weights in g mol-1:

H=1; N=14 O=16; S=32 Cl=35.5; Ca=40 Ni=59

MEDIUM
For a family, there are 150 units consumption of energy, what is the value of this consumption in Joule? 
MEDIUM
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?

(Atomic weight: Mg = 24)
HARD
A mixture of 100 m mol of Ca(OH)2 and 2 g of sodium sulphate was dissolved in water and the volume was made up to 100 mL. What is the mass of calcium sulphate formed and the concentration of OH- in resulting solution, respectively? (Molar mass of CaOH2, Na2SO4 and CaSO4 are 74, 143  and 136 gmol-1, respectively; Ksp of CaOH2 is5.5×10-6)
EASY
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)
EASY
1 gram of a carbonate M2CO3 on treatment with excess HCl produces 0.01186 moles of CO2 . The molar mass of M2CO3 in  gmol-1 is:
MEDIUM

In the following reaction:

A+2B+3CAB2C3
6.0 g of A, 6.0×1023  atoms of B and 0.036 mol of C reacted and formed 4.8 g of compound AB2C3. If the atomic mass of A  and C are 60 and 80 amu, respectively. What is the atomic mass of B in amu? (Avogadro number=6×1023)

EASY
The nearest star to our solar system is 4.3 light years away. The distance of this star in Parsec is (Mean distance between the earth and the sun =1.5×1011 m and one light year =9.46×1015 m
HARD
0.27 g of a long chain fatty acid was dissolved in 100 cm3 of hexane. 10 mL  of this solution was added dropwise to the surface of water in a round watch glass. Hexane evaporates and a monolayer is formed. The distance from edge to centre of the watch glass is 10 cm . What is the height of the monolayer?
[Density of fatty acid =0.9 g cm-3;π=3]