which of the following are chemical changes? A) Cooking of Food B) Digestion of Food C) Freezing of water D) Water is heated up

Correct Answer: Chlorine

Explanation:

Chlorine is the most commonly used bleaching agent.

 

Bleaching agents are compounds which are used to remove color from substances such as textiles. A bleaching agent is a material that lightens or whitens a substrate through the chemical reaction. The bleaching reactions usually involve oxidative or reductive processes that degrade color systems.

Correct Answer: 2.5

Explanation:

Bond Order  = 1/2[ Nb - Na]

where

Nb = Number of electrons in bonding molecular orbitals.

Na = Number of Electrons in antibonding molecular orbitals

 

Bond Order of N2?:

Total number of electrons: 13

Electronic Configuration= :?1s² ?*1s² ?2s² ?*2s² ? 2py² [?2pz² ?2px1 ]

Bond Order = [9-4]/2 = 5/2 = 2.5.

Correct Answer: Stratosphere

Explanation:

Most of the ozone in the atmosphere is found in the layer of stratosphere, which begins about 10.16 kilometers (6.10 miles) above Earth's surface and extends up to about 50 kilometers (31 miles) altitude.

Correct Answer: Isotopes

Correct Answer: Isotones

Correct Answer: Tuberculosis

Explanation:

Para-amino salicylic acid (PAS) is used in the treatment of Tuberculosis.

Correct Answer: 1 proton only

Explanation:

The nucleus of hydrogen consists of only a single proton.

Its parts are a single negatively-charged electron that circles a single positively-charged nucleus of the hydrogen atom.

The electron is bound to the nucleus by the Coulomb force.

Correct Answer: Polarity :: The polarity of a molecule defines its other physical properties such as melting point, boiling point, surface tension, vapor pressure etc Simply, polarity occurs when the electron distribution in a molecule is asymmetric This results in a net dipole moment in the molecule One end of the molecule is charged negative while the other gets a positive charge The polarization of a molecule greatly depends on the shape of the molecule A diatomic molecule like HF mentioned above has no issue of shape The net dipole moment is only due to the uneven distribution of electrons between the two atoms However, when there are more than two atoms involved in making a bond, there are many complexities The water molecule is of bent shape Therefore, when the two pair of electrons shared by oxygen with two hydrogen atoms is pulled towards oxygen, the net dipole moment results in the direction of the oxygen atom There is no other force to cancel out the resultant dipole moment Hence, the water molecule is highly polar Ammonia molecule is of a pyramid shape and the electronegative N atom pulls the electrons towards itself The three N-H bonds are not in the same plane; hence the dipole moments created do not get canceled out This makes ammonia a polar molecule However, the dipole moments sometimes get canceled due to the shape of the molecules, making the molecule non-polar Carbon dioxide is such a molecule

Correct Answer: Amino acids

Explanation:

Proteins are long chains of Amino acids. That is in brief, Amino acids are the monomers of Proteins. Amino acids are compounds which contain both an amino group and a carboxylic group. Proteins are made up of 20 essential amino acids.

Monomer means a small molecule of an organic substance i.e, building block in general.

 

Correct Answer: Methanol (CH3OH)

Explanation:

Chemical Compounds with stronger intermolecular forces have higher boiling points.

 

The order of strengths of intermolecular forces is:

 London dispersion < dipole-dipole < H-bonding

 

${\text{Methane (CH}}_{\mathrm{4)}}$ ? London dispersion forces

${\text{Dimethyl ether (CH}}_3{\text{OCH}}_{\mathrm{3)}}$ ? dipole-dipole attractions

${\text{Methanol (CH}}_3\text{OH)}$ ? hydrogen bonding

Therefore, ${\text{Methanol -}}^{}$${\text{CH}}_3\text{OH}$$\text{with H-Bonding have highest Boiling Point among the given chemical compounds.}$