Chapter 1 Chemical Equations And Reactions

2.

In a reaction between sulphuric acid and barium chloride solution the white precipitate are of:

Hydrochloric acid
Barium sulphate
Chlorine
Sulphur

Correct Answer

A. Barium sulphate

Explanation

In a reaction between sulphuric acid and barium chloride solution, a white precipitate is formed. This white precipitate is known as barium sulphate.

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3.

All the methods mentioned below can be used to prevent the food from getting rancid except: I. storing the food in the air tight containers. II. storing the food in refrigerator III. keeping the food in clean and covered containers. IV. always touching the food with clean hands.

(I) and (II)
(I) and (III)
(I),(III) and (IV)
(III) and (IV)

Correct Answer

A. (III) and (IV)

Explanation

Storing the food in air tight containers and storing the food in the refrigerator both help to prevent the food from getting rancid by limiting exposure to air and controlling the temperature. However, keeping the food in clean and covered containers and always touching the food with clean hands do not directly prevent the food from getting rancid. These practices are important for maintaining hygiene and preventing contamination, but they do not specifically address the issue of food rancidity.

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4.

A substance which oxidized itself and reduced other is known as:

Oxidizing agent
Reducing agent
Both of these
None of the above

Correct Answer

A. Reducing agent

Explanation

A reducing agent is a substance that donates electrons to another substance, causing it to be reduced. In this case, the substance oxidizes itself by losing electrons and at the same time reduces another substance by donating those electrons. Therefore, the correct answer is reducing agent.

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5.

The equation: Cu + xHNO₃-------> Cu(NO₃)₂+ yNO₂+ 2H₂O the values of x and y are:

3 and 5
8 and 6
4 and 2
7 and 1

Correct Answer

A. 4 and 2

Explanation

In the given equation, Cu reacts with HNO3 to form Cu(NO3)2, NO2, and H2O. The balanced equation shows that for every 1 mole of Cu, 4 moles of HNO3 are required. This means that x must be equal to 4. Additionally, the equation shows that for every 1 mole of Cu, 2 moles of NO2 are produced. This means that y must be equal to 2. Therefore, the values of x and y are 4 and 2, respectively.

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6.

When copper powder is heated it gets coated with

Black copper oxide
Yellow copper oxide
Red copper oxide
None of the above

Correct Answer

A. Black copper oxide

Explanation

When copper powder is heated, it undergoes a chemical reaction with oxygen in the air, resulting in the formation of black copper oxide. This black coating is a result of the copper atoms combining with oxygen atoms to form copper oxide. This reaction is commonly known as oxidation and is responsible for the black color observed on the surface of the copper powder.

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7.

Black and white photography uses:

Decomposition of silver chloride
Decomposition of silver bromide
Both
None of the above

Correct Answer

A. Both

Explanation

Black and white photography uses both the decomposition of silver chloride and the decomposition of silver bromide. In traditional black and white film photography, silver halide crystals (such as silver chloride or silver bromide) are used to capture light and create an image. When exposed to light, these crystals undergo a chemical reaction called decomposition, which forms metallic silver particles. These silver particles are then developed and fixed onto the film, resulting in a black and white image. Therefore, both silver chloride and silver bromide are used in the process of black and white photography.

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8.

Combination of phosphorus and oxygen is an example of________

Correct Answer
oxidation reaction

Explanation
A combination of phosphorus and oxygen is an example of an oxidation reaction because oxidation involves the loss of electrons or an increase in the oxidation state of an element. In this case, phosphorus is being oxidized as it gains oxygen atoms and increases its oxidation state.

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9.

Which of the following gases is used in the storage of fat and containing foods for a long time?

Carbon dioxide
Nitrogen
Oxygen
Neon

Correct Answer

A. Nitrogen

Explanation

Nitrogen is used in the storage of fat and containing foods for a long time because it is an inert gas. It helps to create a controlled environment by displacing oxygen, which slows down the oxidation process and prevents the growth of bacteria and other microorganisms. This helps to extend the shelf life of the food and maintain its quality for a longer period of time.

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10.

An element X on exposure to moist air turns reddish brown and a new compound Y is formed. the substance X and Y are :

X=fe , Y=fe₂O₃
X=Ag , Y= Ag₂S
X=Cu , Y=CuO
X =Al , Y= Al₂O₃

Correct Answer

A. X=fe , Y=fe₂O₃

Explanation

When element X (fe) is exposed to moist air, it undergoes a chemical reaction and turns reddish brown. This indicates the formation of a new compound Y (fe2O3), which is iron(III) oxide. Iron(III) oxide is commonly known as rust and is formed when iron reacts with oxygen in the presence of moisture. Therefore, the correct answer is X=fe, Y=fe2O3.

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Chapter 1 Chemical Equations And Reactions

Electrolysis of water is decomposition reaction. the mole ratio of hydrogen and oxygen gases liberation during electrolysis of water is.

Quiz Preview

In a reaction between sulphuric acid and barium chloride solution the white precipitate are of:

All the methods mentioned below can be used to prevent the food from getting rancid except: I. storing the food in the air tight containers. II. storing the food in refrigerator III. keeping the food in clean and covered containers. IV. always touching the food with clean hands.

A substance which oxidized itself and reduced other is known as:

The equation: Cu + xHNO₃-------> Cu(NO₃)₂+ yNO₂+ 2H₂O the values of x and y are:

When copper powder is heated it gets coated with

Black and white photography uses:

Combination of phosphorus and oxygen is an example of________

Which of the following gases is used in the storage of fat and containing foods for a long time?

An element X on exposure to moist air turns reddish brown and a new compound Y is formed. the substance X and Y are :

Chapter 1 Chemical Equations And Reactions

Electrolysis of water is decomposition reaction. the mole ratio of hydrogen and oxygen gases liberation during electrolysis of water is.

Quiz Preview

In a reaction between sulphuric acid and barium chloride solution the white precipitate are of:

All the methods mentioned below can be used to prevent the food from getting rancid except: I. storing the food in the air tight containers. II. storing the food in refrigerator III. keeping the food in clean and covered containers. IV. always touching the food with clean hands.

A substance which oxidized itself and reduced other is known as:

The equation: Cu + xHNO3 -------> Cu(NO3)2 + yNO2 + 2H2O the values of x and y are:

When copper powder is heated it gets coated with

Black and white photography uses:

Combination of phosphorus and oxygen is an example of________

Which of the following gases is used in the storage of fat and containing foods for a long time?

An element X on exposure to moist air turns reddish brown and a new compound Y is formed. the substance X and Y are :

The equation: Cu + xHNO₃-------> Cu(NO₃)₂+ yNO₂+ 2H₂O the values of x and y are: