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Q:

In modern periodic table while going from top to bottom in a group ______.

 

A) size of an atom increases B) size of an atom decreases
C) ionisation energy of an atom increases D)  size and ionisation energy of an atom increases

Answer:   D)  size and ionisation energy of an atom increases



Explanation:
Subject: Chemistry
Exam Prep: Bank Exams
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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)

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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.

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47 11127
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.

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0 3516
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.

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41 16202
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

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1 3629
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

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2 2768
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.

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1 2950
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.

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Exam Prep: AIEEE

4 3440