Test: Combination And Decomposition Reaction


15 Questions MCQ Test Science Class 10 | Test: Combination And Decomposition Reaction


Description
This mock test of Test: Combination And Decomposition Reaction for Class 10 helps you for every Class 10 entrance exam. This contains 15 Multiple Choice Questions for Class 10 Test: Combination And Decomposition Reaction (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Combination And Decomposition Reaction quiz give you a good mix of easy questions and tough questions. Class 10 students definitely take this Test: Combination And Decomposition Reaction exercise for a better result in the exam. You can find other Test: Combination And Decomposition Reaction extra questions, long questions & short questions for Class 10 on EduRev as well by searching above.
QUESTION: 1

Which of the following product is formed when calcium oxide reacts with water?

Solution:

When calcium oxide (chemical formula: Ca0) reacts with water (chemical formula: H20), the following reaction takes place:

The product of this reaction is calcium hydroxide, also known as slaked lime. Thus, when calcium oxide reacts with water, slaked lime is produced. 

QUESTION: 2

We use a solution of slaked lime to whitewash the walls. In the beginning the wall looks rough and coarse, but after 2 – 3 days the wall appears smooth and shiny. This is due to the formation of:

Solution:

Slaked lime is calcium hydroxide which reacts slowly with the carbon dioxide present in air to form thin and shiny layer of calcium carbonate. The chemical reaction is:
Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)

QUESTION: 3

The reaction of calcium oxide with water to form calcium hydroxide is an example of:

Solution: It is a Combination reaction because two elements or compounds (Calcium oxide and water) combine together to form a single product ( Calcium Hydroxide). So it's a combination reaction. It is exothermic because evolution of heat is also involved in the reaction.
QUESTION: 4

Combination reactions can take place between:

Solution:

A chemical change must occur which is generally observed with physical changes like precipitation, heat production, color change etc. A reaction can take place between two atoms or ions or molecules and they form a new bond and no atom is destroyed or created but a new product is formed from reactants. The rate of reaction depends on and is affected by factors like pressure, temperature, the concentration of reactants.

QUESTION: 5

CaO + H2O → Ca(OH)2 is an example of a:

Solution: Reaction in which two or more reactant combines to form single product is said to be combination reaction. here, reactant is 2 and product is 1. 
QUESTION: 6

An example of combination reaction between an element and compound is:

Solution:

 

Sulphur dioxide is a compound and oxygen is in elemental form. They combine to form sulphur trioxide.

QUESTION: 7

Which of the following reaction requires light?

Solution:

Photodissociation, photolysis, or photodecomposition is a chemical reaction in which a chemical compound is broken down by photons. It is defined as the interaction of one or more photons with one target molecule. Photodissociation is not limited to visible light.

QUESTION: 8

Which of the following is a combination reaction?

Solution:

A reaction in which two or more reactants combine together to form a single product.
Example : C + O2 → CO2

QUESTION: 9

Which of the following decomposition reaction occurs with the absorption of electrical energy?

Solution:

QUESTION: 10

2NO + O2 → 2NOis an example of :

Solution:

Combination reaction
A chemical reaction in which two or more substances combine to form a single new substance is called a combination reaction.
Representation: A + B → AB

QUESTION: 11

When a magnesium ribbon is burnt in air, the ash formed is     

Solution:

When a magnesium ribbon is burned in air, it burns with a dazzling white flame producing white ash.

Yes, Mg is oxidized.

2Mg + O2 → 2MgO

QUESTION: 12

Which of the following does denote chemical reaction take place?

Solution:

A Chemical Reaction is a process that occurs when two or more molecules interact to form a new product(s)

QUESTION: 13

Which of the following product is formed after heating of limestone?

Solution:

The chemical reaction that takes place when limestone is heated is
CaCo3 → CaO + CO2.

QUESTION: 14

Which of the following is a use of an electrolytic decomposition reaction?

Solution:

Electrolytic decomposition reactions are used to obtain metals from their chloride or oxide ores.

QUESTION: 15

A student uses lime water to test the gas evolved as a result of action of dilute HCl on solid sodium carbonate. The chemical compound present in lime water is :

Solution:

The Chemical Formula of lime water is Ca(OH)2 (Calcium Hydroxide).

Related tests