Tag: structure and properties of water

Questions Related to structure and properties of water

By this process, water can be purified in a simple way:

  1. Freezing

  2. Melting

  3. Boiling

  4. Evaporating


Correct Option: C
Explanation:

By boiling, water can be purified in a simple way as the nonvolatile impurities remain back and pure water is condensed separately.

Which of the following is NOT soluble in water?

  1. Salt

  2. Sugar

  3. Oxygen

  4. Sand


Correct Option: D
Explanation:

Sand $(SiO _2)$ is not soluble in water.

Which property of water is used while washing clothes?

  1. Odour

  2. Colour

  3. Solubility

  4. Sand


Correct Option: C
Explanation:

Water is a good solvent. It combine with dirt and other particles with it when treated with soap, which is water soluble and form lather in water. Hence due to its solubility it is used while washing clothes. 

Statement 1: Water boils below ${100}^{o}C$ at high altitudes. 
Statement 2: Atmospheric pressure varies inversely with altitude.

  1. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  2. Both the Statement 1 and Statement 2 are correct and Statement 2 is NOT the correct explanation of Statement 1.

  3. Statement 1 is correct but Statement 2 is not correct.

  4. Statement 1 is not correct but Statement 2 is correct.

  5. Both the Statement 1 and Statement 2 are not correct.


Correct Option: A
Explanation:

Pressure changes inversely with altitudes and boiling point directly proportional to pressure. Pressure and boiling points are low at high altitudes. So water boils below 100$ ^{\circ}C $.

Temporary hardness is caused due to the presence of:

  1. magnesium sulphate

  2. magnesium chloride

  3. calcium sulphate

  4. magnesium carbonate


Correct Option: D
Explanation:

Temporary hardness is caused due to the presence of carbonates of calcium and magnesium which can be removed by boiling the water.

Permanent hardness is caused due to:

  1. magnesium bicarbonate

  2. magnesium carbonate

  3. magnesium sulphate

  4. all of the above


Correct Option: C
Explanation:

Temporary hardness causes due to the presence of carbonates and bicarbonate ans permanent hardness is caused due to the presence of chlorides and sulphates.

Water has maximum density at

  1. Room temperature

  2. ${4}^{o}C$

  3. ${0}^{o}C$

  4. $-{4}^{o}C$


Correct Option: B
Explanation:
When Water is in its Solid Form (Ice) below $0^0 C$, it is forced into a regular Cage like Structure with small voids due to which the Volume of Ice is larger.
At $4^0 C$, the Cage like Structure of Ice starts to break and the molecules can slide along each other, closing the empy voids due to which momentarily the Volume of Water decreases. Due to decrease in Volume, Density increases because Density is inversely proportional to Volume.
As temperature rises to over $4^0 C$, the extra space needed by increased motion of water molecules starts being larger than the space gained due to structural changes and the molecules start to move away from each other due to which the Volume again increases and Density decreases.

Thus, Density maximum is reached at $4^0C$.

Molecular mass of water ______.

  1. $18 u$

  2. $16 u$

  3. $15 u$

  4. $10 u$


Correct Option: A
Explanation:

As we know the molecular formula of water is H2O which means that one molecule of water contain 2 atoms of hydrogen and 1 atom of oxygen.

Then weight of 1 atom of hydrogen= 1 u

so weight of 2 atom= 2 u

Weight of 1 atom of oxygen= 16 u

Then molecular weight of water= 2* weight of 1 atom of hydrogen+ weight of 1 atom of oxygen

Thus molecular weight of water is approximately 2+16 u = 18 u

During hydrate formation from aqueous solution water can be associated in different forms. Indicate the wrong combination. 
Coordinated water -$[Cr(H _{2}O) _{6}]^{3+}3Cl^{-}$
Interstitial water - $BaCl _{2}.2H _{2}O$
Hydrogen bonded water --$[Cu(H _{2}O) _{4}]^{2+}SO _{4}^{2-}.H _{2}O$

  1. (i)

  2. (ii)

  3. (iii)

  4. none of these


Correct Option: D
Explanation:
Coordinated water is water that is a ligand in a metal complex. The metal atom and the water molecules are held together by coordinate bonds.
Interstitial water is water that is present in the interstitial sites of a crystal lattice.
Hydrogen-bonded water is the water that that is linked to some other ion by hydrogen bonding.

A teacher one day pointed out to his students the peculiar fact that water is a unique liquid that freezes exactly at $0^oC$ and boils exactly at $100^oC$. He asked the students to find the correct statement based on this fact.


Which of the statements is true regarding the above fact?

  1. Water dissolves anything however sparingly the dissolution may be.

  2. Water is a polar molecule.

  3. Boiling and freezing temperatures of water were used to define a temperature scale.

  4. Liquid water is denser than ice.


Correct Option: C
Explanation:

Option (C) is correct.
Boiling and freezing temperatures of water were used to define a temperature scale.The scaling of zero degree centigrade is based on this fact.