AP BIOLOGY

BIOCHEMISTRY

PROPERTIES OF WATER

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Why is water considered a polar molecule?
A
The oxygen end is slightly negative and the hydrogen end is slightly positive
B
The hydrogen end is slightly negative and the oxygen end is slightly positive
C
The hydrogen and oxygen are covalently bonded
D
Because it is hydrophobic
Explanation: 

Detailed explanation-1: -Water (H2O) is a polar molecule because the electrons of the hydrogen atoms get “pulled” towards the electrons of the oxygen atom. This makes a region of positive charge on the hydrogen atoms and the negative charge on the other end of the molecule, which is the oxygen atom.

Detailed explanation-2: -The unequal sharing of electrons between the atoms and the unsymmetrical shape of the molecule means that a water molecule has two poles-a positive charge on the hydrogen pole (side) and a negative charge on the oxygen pole (side). We say that the water molecule is electrically polar.

Detailed explanation-3: -Because oxygen and hydrogen attract the shared electrons unequally, each end of the V-shaped H2O molecule adopts a slightly different charge. The area around the oxygen is somewhat negative compared to the opposite, hydrogen-containing end of the molecule, which is slightly positive.

Detailed explanation-4: -In the covalent bond between oxygen and hydrogen, the oxygen atom attracts electrons a bit more strongly than the hydrogen atoms. The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms.

Detailed explanation-5: -Water (H2O) is polar because of the bent shape of the molecule. The shape means most of the negative charge from the oxygen on side of the molecule and the positive charge of the hydrogen atoms is on the other side of the molecule. This is an example of polar covalent chemical bonding.

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