Sawaal
13
Q:

Which of the following reactions are exothermic?

 

1)   C + O2  → CO22)  2Mg + O2  → 2MgO3)  CuSO4 + 5H2O  → CuSO4.5H2O4)  All the above

A) 1 B) 2
C) 3 D) 4

Answer:   D) 4



Explanation:

Here all the given options are Exothermic reactions. Exothermic reactions are those reactions which involves the release of heat.

 

Generally all the combining reactions are exothermic in nature.

Subject: Chemistry
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Analyst , Bank Clerk , Bank PO
Related Questions
Q:

One of the ingredients of the paste on the side of a match box is 

A) Phosphorus pentaoxide B) Phosphorus trichloride
C) Phosphorus trisulphide D) Phosphorus trioxide
 
Answer & Explanation Answer: C) Phosphorus trisulphide

Explanation:

The paste applied to the side of a match box is a mixture of phosphorus trisulphide, glass powder (or sand) to cause friction and glue (binding material)

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry

3 3405
Q:

The metal which reacts most violently with with cold water is

A) calcium B) sodium
C) magnesium D) potassium
 
Answer & Explanation Answer: D) potassium

Explanation:

Potassium reacts violently with water liberating hydrogen. The reaction is so violent that the liberated hydrogen catches fire.

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry

47 11119
Q:

Water always contains hydrogen and oxygen in the ratio 1:8 by weight.This is in accordance with the 

A) Law of Multiple Proportions B) Law of Definite Proportion
C) Law of Conservation of mass D) Law of Reciprocal Proportions
 
Answer & Explanation Answer: B) Law of Definite Proportion

Explanation:

The Law of Definite Proportion states that the same compound, wherever found or however made, always contains the same elements combined together in the same fixede ratio by weight.

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry

0 3515
Q:

Temporary hardness is due to the presence of 

A) Calcium carbonate B) calcium bicarbonate
C) magnesium sulphate D) calcium sulphate
 
Answer & Explanation Answer: B) calcium bicarbonate

Explanation:

Temporary hardness is due to the presence of soluble bicarbonates of calcium and magnesium in water. Permanent hardness is due to the presence of sulphates and chlorides of calcium and magnesium.

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry

41 16201
Q:

Harmful bacteria in drinking water cannot be destroyed by 

A) Chlorination B) boiling
C) adding caustic soda D) ozonisation
 
Answer & Explanation Answer: C) adding caustic soda

Explanation:

Water containing caustic soda cannot be used for drinking

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry

1 3620
Q:

The function of nitrogen in air is 

A) to make air a moderate supporter of combustion B) to maintain the density of air constant
C) to prevent the hydrogen in air from exploding D) to reduce the poisonous nature of ozone in air
 
Answer & Explanation Answer: A) to make air a moderate supporter of combustion

Explanation:

If air contained all oxygen and no nitrogen, everything would have burnt off

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry

2 2759
Q:

The process that takes place in the atom bomb is

A) nuclear fusion B) nuclear fission
C) radioactive disintegration D) chemical decomposition
 
Answer & Explanation Answer: B) nuclear fission

Explanation:

In the atom bomb, isotopes of uranium are  disintegrated with the release of a large amount of energy. Hence, the process is nuclear fission.

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry

1 2948
Q:

Alum is used 

A) as an analgesic B) in the purification of water
C) as a fertilizer D) as a disinfectant
 
Answer & Explanation Answer: B) in the purification of water

Explanation:

Alum is a common alum, potassium aluminum sulphate K2SO4.Al2SO43.24H2O which makes colloidally suspended impurities in water such as clay to settle down.

Report Error

View Answer Report Error Discuss

Filed Under: Chemistry
Exam Prep: AIEEE

4 3437