NCERT based chemistry questions answers are commonly asked in many competative exams like JEE Mains, UPSC, SSC, NEET, HSSC, FCI, LDC and TET exams. It includes chemical reaction and equation mcq, chemistry questions on periodic table etc. Here, we are providing you important Chemistry Questions and Answers for those learners who are preparing for competitive exams.
|
Q 31.
What are Sulpher, Sugar, Nitrogen are ?
Ans.
All are non-metal.
|
|
Q 32.
Name the process by which cooking oil can be converted into vegetable ghee ?
Ans.
Hydrogenation.
|
|
Q 33.
What is lime water contains ?
Ans.
Calcium hydroxide.
|
|
Q 34.
The product of equivalent weight and valency of an element is equal to ?
Ans.
Atomic weight.
|
|
Q 35.
What is the best standard atomic mass ?
Ans.
Carbon -12.
|
|
Q 36.
Why detergents produce hard water ?
Ans.
Because the calcium and magnesium salts of sulphonic acids are soluble in water.
|
|
Q 37.
What is synthetic detergents ?
Ans.
It is a mixture of sodium salt of aromatic and aliphatic sulphonic acids.
|
|
Q 38.
Who enunciated the law of constant proportions ?
Ans.
Proust.
|
|
Q 39.
What is laundry soap made of ?
Ans.
A mixture of sodium salts of higher fatty acids of natural origin.
|
|
Q 40.
Sodium carbonate crystals lose water molecules.This property is called ?
Ans.
Efflorescence.
|
|
Q 41.
What is chemically baking soda ?
Ans.
Sodium bicarbonate.
|
|
Q 42.
Name the scientist who stated that matter can be converted into energy ?
Ans.
Einstein.
|
|
Q 43.
Why water on passing over rocks becomes hard ?
Ans.
Because it dissolves calcium carbonate.
|
|
Q 44.
What is an alloy ?
Ans.
A mixture.
|
|
Q 45.
Why hard water does not lather well with soap ?
Ans.
Because it contains carbonates of calcium and magnesium.
|
|
Q 46.
Which is the most abundant metal in the earth crust ?
Ans.
Aluminium.
|
|
Q 47.
What is washing soda ?
Ans.
Hydrated sodium carbonate.
|
|
Q 48.
A pure substance can only be ?
Ans.
An element or compound.
|
|
Q 49.
An electric kettle used for boiling hard water has a white scale deposited on its heating element. This consist of ?
Ans.
Carbonates of calcium and magnesium.
|
|
Q 50.
What is the name of father of modern chemistry ?
Ans.
Lavoisier.
|
|
Q 51.
Name the process by which common salt is obtained from sea water ?
Ans.
Evaporation.
|