Chemistry Questions

Q:

The reduction potential of hydrogen half-cell will be negative if :
(1) PH2= 2 atm and [H+] = 2.0 M
(2) PH2= 1 atm and [H+] = 2.0 M
(3) PH2= 1 atm and [H+] = 1.0 M
(4) PH2= 2 atm and [H+] = 1.0 M

A) Option 1 B) Option 2
C) Option 3 D) Option 4
 
Answer & Explanation Answer: D) Option 4

Explanation:

 H+-e-12H2   

Apply Nernst equation  

 

E=0-0.0591logPH212H+  

 

 E=-0.0591log2121  

 

Therefore E is Negative

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Q:

Which of the following statements are CORRECT?

 


I. The soap molecules form structures called micelles.


II Soap micelles cannot scatter light.


III. Oily dirt gets collected in the center of the micelle.

 

A) Both I and II B) Both I and III
C) Both II and III D) All I, II and III
 
Answer & Explanation Answer: B) Both I and III

Explanation:
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Q:

The properties of several unknown solids were measured. Choose the correct option.

 

 

 

A) A, C B) A, C, D
C) B, D D) A, B, C, D
 
Answer & Explanation Answer: D) A, B, C, D

Explanation:
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Q:

Which combination of atoms can form a polar covalent bond?

A) H and Br B) H and H
C) Na and Br D) N and N
 
Answer & Explanation Answer: A) H and Br

Explanation:

Only H and Br form Polar Covalent Bond.

 

Covalent bonding:

Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.

1. Polar Covalent Bond

2. Nonpolar Covalent Bond

 

1. Polar Covalent Bond:

A Polar Covalent Bond is created when the shared electrons between atoms are not equally shared. This occurs when one atom has a higher electronegativity than the atom it is sharing with. The atom with the higher electronegativity will have a stronger pull for electrons (Similiar to a Tug-O-War game, whoever is stronger usually wins). As a result, the shared electrons will be closer to the atom with the higher electronegativity, making it unequally shared.

 

2. Nonpolar Covalent Bond:

A Nonpolar Covalent Bond is created when atoms share their electrons equally. This usually occurs when two atoms have similar or the same electron affinity. The closer the values of their electron affinity, the stronger the attraction. This occurs in gas molecules; also known as diatomic elements. Nonpolar covalent bonds have a similar concept as polar covalent bonds; the atom with the higher electronegativity will draw away the electron from the weaker one.

 

Here H and H and N and N form Non-polar covalent bonds. Na and Br form the ionic bond.

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Q:

The most reactive of the following metals is

 

A) Al B) Ca
C) Ni D) Pb
 
Answer & Explanation Answer: B) Ca

Explanation:
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Q:

Which one is not metal

A) sulpher B) sugar
C) nitogen D) all of these
 
Answer & Explanation Answer: D) all of these

Explanation:
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Q:

Which type of reaction occurs when carbon burns in oxygen to give carbo dioxide?

 

A) Addition reaction B) Substition reaction
C) Combustion reaction D) Decomposition reaction
 
Answer & Explanation Answer: C) Combustion reaction

Explanation:
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Q:

An electron loses potential energy when it

 

A) shifts to a more electronegative atom. B) increases its kinetic energy.
C) shifts to a less electronegative atom. D) increases its activity as an oxidizing agent.
 
Answer & Explanation Answer: A) shifts to a more electronegative atom.

Explanation:
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