Tag: chemistry

Questions Related to chemistry

Boiling point of a substance is based on the intermolecular and intramolecular forces which in turn determine the lattice energy of a substance.
Which of the following substance would have the highest boiling point?

chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

  1. $NaCl$

  2. $Hg$

  3. $AlF _{3}$

  4. $H _{2}O$

Show answer
Correct Option: A
Explanation:

$NaCl$ will have the highest boiling point as it is the strongest ionic compound present in the given options. $NaCl$ have strong interionic forces as $Na^+$ and $Cl^-$ attracts each other very strongly which results in an increase in the compactness of the molecule, further its lattice enthalpy.

We have all heard the phrase "opposites attract but like repels." This is especially true for ionic compounds.
Which one of the following has the largest lattice energy as a result of this attraction?

chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

  1. $LiCl$

  2. $NaCl$

  3. $K _{2}O$

  4. $MgCl _{2}$

Show answer
Correct Option: A
Explanation:

$LiCl$. $Li^+$ due to its small size and has high polarizing power and attracts the electron cloud of $Cl^-$ towards itself which results in high lattice energy of the molecule.

Considering only  lattice enthalpy, arrange them in the increasing order of their stability:
$NaCl$ , $MgCl _{2}$ , $MgO$

chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

  1. $NaCl$ , $MgO$, $MgCl _{2}$

  2. $NaCl$ , $MgCl _{2}$ , $MgO$

  3. $MgCl$, $MgO$, $MgCl _{2}$

  4. none of these

Show answer
Correct Option: B
Explanation:

Lattice enthalpy is a measure of the strength of the forces between the ions in an ionic solid. The greater the lattice enthalpy, the stronger the forces. 

Lattice enthalpy of $ NaCl $ = $787kJ/mol$
Lattice enthalpy of $ MgO $ = $3826kJ/mol$
Lattice enthalpy of $Mg{ Cl } _{ 2 }$= $+2534kJ/mol$

The correct order of the lattice energies of the following ionic compound is :

chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

  1. $NaCl > MgBr _2 > CaO > Al _2O3$

  2. $NaCl > CaO > MgBr _2 > Al _2O _3
    $

  3. $Al _2O _3 > MgBr _2 > CaO > NaCl$

  4. $Al _2O _3 > CaO > MgBr _2 > NaCl$

Show answer
Correct Option: D
Explanation:

Charge matter in lattice energy so here $Al^{+3}, Ca^{+2}, Mg^{+2}, Na^+$ and $O^{-2}$ & $Br^{-1}$
So $cao>MgBr _2 \Rightarrow$ overall order $Al _2O _3>Cao>MgBr _2>NaCl.$

$MgO$ has a high melting point because due to the highly charged ions, ionic force is strong and lattice energy is........

chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

  1. High

  2. Low

  3. Both are

  4. None of these

Show answer
Correct Option: A
Explanation:

lattice energy is high

In magnesium oxide, both magnesium and oxygen atoms form ions in the lattice. Due to the higher magnitude of the charge on the magnesium and oxygen atoms, the force of attraction between them is very high. This provides them with very high lattice energy and a lot of energy is required to break this lattice. Hence the melting point of $MgO$ is high. Therefore both the statements are correct and statement 2 is the correct explanation for statement 1

What is scouring ?

chemistry natural fibres wool - animal fibre wool fibres from animals

  1. Removal of dust, impurity and grease from hair of sheep

  2. Removal of water from hair of sheep

  3. Removal of other hairs from hair of sheep

  4. None of these

Show answer
Correct Option: A
Explanation:

$A$ 

This is the second step in obtaining fiber. The woolen fibers are thoroughly washed in big tanks to remove grease, dust and dirt by fully mechanized machines before the wool can be used for commercial purposes.. Wool straight off a sheep, known as "greasy wool” or "wool in the grease", contains a high level of valuable lanolin, as well as the sheep's dead skin and sweat residue, and generally also contains pesticides and vegetable matter from the animal's environment. 

Group of animals which gives wool are:

chemistry materials of daily use wool - animal fibre wool fibres from animals

  1. Sheep, goat, camel and yak

  2. Sheep camel, lion and rabbit

  3. Rabbit, silkworm, buffalow and cow

  4. Goat, cat, sheep and camel

Show answer
Correct Option: A
Explanation:

There are many animals that bear a thick coat of hair on their body which gives wool to us for example sheep, goat, camel and yak.

Which of the following is/are Indian breed of sheep?

chemistry materials of daily use wool - animal fibre wool fibres from animals

  1. Beetal

  2. Barbari

  3. Jamunapari

  4. all of them

Show answer
Correct Option: D
Explanation:

$Beetal, Barbari, Jamunapari$ all are Indian breeds of sheep. Beetal are found mainly in the states of Punjab, Barbari is found in Delhi, Uttar Pradesh, Gurgaon, Karnal, panipat and Rohtak in Haryana state and Jamunapari breeds are found mainly in the state of Uttar Pradesh.

Which of the following are fleece and wool-bearing animals?

chemistry materials of daily use wool - animal fibre wool fibres from animals

  1. Sheep and goat

  2. Camel and Yak

  3. Both A and B

  4. none of them

Show answer
Correct Option: C
Explanation:

Sheep, goat, Camel, Yak, etc. bear hair of two different types coarse hair and fine soft hair. Fine soft hair is found close to the skin in these animals. The fine soft under hair is called fleece. Fibre for wool is obtained from the fleece (hair) of such animals and hence such animals are called wool-bearing animals.

The Indian goat breeds Jamunapari is found in:

chemistry materials of daily use wool - animal fibre wool fibres from animals

  1. Uttar Pradesh

  2. Madhya Pradesh

  3. Himachal Pradesh

  4. Haryana

Show answer
Correct Option: A
Explanation:

Jamunapari breeds are found mainly in the state of Uttar Pradesh. These goats are generally found in white colour.


Hence, option $\text A $ is correct.