Online Test of Chapter 1 Chemical Reactions and Equations 1 Science| Class 10th

Q1. A chemical reaction has taken place in which of the following process?
(i) Ice melts into water
(ii) A wet shirt got dried in sunlight
(iii) A brown layer is formed over iron rod kept in air
(iv) Sugar getting dissolved in water

Q2. Which of the following is not a chemical Reaction?
(i) Formation of salt solution
(ii) Milk turns sour in hot weather
(iii) Burning of match stick
(iv) Contamination of food

Q3. A chemical reaction has taken place can be represented by which of the following condition?
(i) Evolution of gas
(ii) Heat released
(iii) Change in color
(iv) All the above

Q4. A chemical equation properly written has which of the following features?
(i)Temperature required
(ii) Should be balanced
(iii) Should have information regarding physical states
(iv) All the above

Q5. A Chemical equation should be balanced to
(i) Display conservation of energy
(ii) Display conservation of mass
(iii) To make equation attractive
(iv) All the above

Q6. An unbalanced chemical equation is equation written in
(i) Skeletal form
(ii) Proper form
(iii) Simple form
(iv) Unorganized form

Q7. A chemical equation is said to be balanced if number of
(i) Compounds are same in both side
(ii) Molecules are same in both side
(iii) Number of atoms is same in both side
(iv) Number of electrons are same in both side

Q8. When magnesium is burnt in air then
(i) Magnesium is reacting with oxygen
(ii) Magnesium is reacting with nitrogen
(iii) Magnesium is reacting with carbon
(iv) Magnesium is reacting with Carbon di oxide

Q9. Write values of a,b and c if following chemical reaction is balanced .
aMg + bO₂ → cMgO
(i) a=1, b=2, c=2
(ii) a=2, b=1, c=2
(iii)a=2,b=2,c=2
(iv) a=1,b=2.c=1

Q10. Write values of a, b and c so that following chemical equation is balanced
aH₂ + bO₂ → cH₂O
(i) a=2,b=1,c=2
(ii) a=1,b=1,c=2
(iii) a=1,b=2,c=1
(iv) a=2,b=2,c=1