Test: Chemical Reactions


15 Questions MCQ Test General Science(Prelims) by IRS Divey Sethi | Test: Chemical Reactions


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This mock test of Test: Chemical Reactions for UPSC helps you for every UPSC entrance exam. This contains 15 Multiple Choice Questions for UPSC Test: Chemical Reactions (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Chemical Reactions quiz give you a good mix of easy questions and tough questions. UPSC students definitely take this Test: Chemical Reactions exercise for a better result in the exam. You can find other Test: Chemical Reactions extra questions, long questions & short questions for UPSC on EduRev as well by searching above.
QUESTION: 1

Reaction between Ammonium chloride and Barium hydroxide is:

Solution:

Reaction between Ammonium chloride and Barium hydroxide is an endothermic reaction.An exothermic reaction is a chemical reaction that releases energy through light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: reactants → products + energy. Exothermic Reaction means "exo" meaning releases and "thermic" means heat.

QUESTION: 2

The reaction of H2 gas with oxygen gas to form water is an example of     

Solution:

Hydrogen is a highly reactive fuel. Hydrogen molecules violently react with oxygen when the existing molecular bonds break and new bonds are formed between oxygen and hydrogen atoms. As the products of the reaction are at a lower energy level than the reactants(i.e products are more stable), the result is an explosive release of energy and the production of water.

Its an example of exothermic reaction
It is an example of Combination reaction as 2 or more reactants combine to form a single product.

As in the given equation, the electrons are transferred from Hydrogen to Oxygen, hence Oxygen is reduced and electrons are accepted by Oxygen from Hydrogen, hence Hydrogen is oxidised .Now,both oxidation and reduction are going together, therefore it is also a Redox (Reduction- Oxidation reaction) reaction.

QUESTION: 3

In a reaction between zinc and hydrochloric acid, the changes accompanying a reaction are:

Solution:

Hydrogen gas and heat are produced in the reaction between zinc and hydrochloric acid.
Zn + HCl → ZnCl2 + H2

QUESTION: 4

If reaction between nitrogen and hydrogen to form ammonia is exothermic, then it will be accompanied by:

Solution:

When chemical reactions take place, energy is either absorbed or evolved. As the given reaction is exothermic, heat must have been evolved.

QUESTION: 5

During an exothermic reaction:

Solution:

An exothermic reaction is a chemical reaction that releases energy through light or heat. It is the opposite of an endothermic reaction.
Expressed in a chemical equation: reactants → products + energy.

QUESTION: 6

The reactions in which precipitate is formed are known as:

Solution:

A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name.
Precipitation reactions can help determine the presence of various ions in solution

QUESTION: 7

An example of a chemical reaction in which heat is evolved is:

Solution:

Sodium metal reacts rapidly with water to form a colorless solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The reaction is exothermic.
2Na(s) + 2H2O → 2NaOH(aq) + H2(g)

QUESTION: 8

An example of reaction in which gas is evolved is:

Solution:

Reaction between limestone(CaCO3) and hydochloric acid(HCl) can be represented by the following formula : CaCO3 + 2HCl → CaCl2 + CO2 ↑ + H2O here, it can be seen that CO2 gas has evolved.

QUESTION: 9

Freezing of water is a:

Solution:

Freezing water is a physical change

QUESTION: 10

An example of reaction in which precipitate is formed is:

Solution:

A precipitation reaction occurs. Yellow precipitates of lead iodide are formed.

The equation for this reaction is Pb(NO3)2 + 2KI → PbI2 + 2KNO3.

The above reaction is a double displacement reaction as well.

QUESTION: 11

An example of a physical change is:

Solution:

Because in physical change the substance change only it's physical appearance but there is no change  in its basic composition that's why we can say that boiling of water is a physical change.

QUESTION: 12

The preparation of water from hydrogen and oxygen gas is accompanied by:

Solution:

Preparation of water from hydrogen and oxygen involves a change in state.

2H2(g) + O2(g) → 2H2O(l)

QUESTION: 13

Which of the following feature is common to both physical and chemical change?

Solution:

If the change of state and colour is a result of some chemical reaction, then the change of state and colour are considered as characteristics of a chemical reaction. 
Otherwise the change of state and colour are considered as characteristics of a physical change.

QUESTION: 14

A drop of colourless liquid is poured over blue litmus paper and it turns to red. The colourless liquid is:

Solution:

Acids turn blue litmus to red hence dilute hydrochloric acid turns blue litmus paper red.

QUESTION: 15

The reaction in which two compounds exchange their ions to form two new compounds is called     

Solution:

The reaction in which two compound exchange their ions to form two new compounds is called double displacement reaction.