Chemistry Questions

The order of basicity for primary, secondary and tertiary amines are:

Secondary > Primary > Tertiary > NH3

* Amines are basic in nature as they have lone pair of electrons on nitrogen. Therefore, they have a strong tendency to donate this lone pair of electrons to electron acceptors.

* The stability of conjugate acids formed is dependent on the extent of H-bonding,and greater the number of H-atoms on N more stable is the conjugate acid.

* The conjugate acid of primary amine is the most stable with greater number (3) of H-bonds than > Secondary > tertiary. But primary amines are less basic than secondary as the electron density on the N atom is less and lone pair of electrons are not readily available for protonation.

* The two opposing factors i.e. the stability of conjugate acids formed and ease of availability of electrons for Protonation, balance each other in case of secondary amines and it is most basic.

'M' is used as a unit of molarity and stands for mole per litre i.e, number of moles of solute per liter of solution.

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

Nitrogen (N2) forms Three Covalent Bonds to become stable.

Here the Atmomic Number of Nitrogen is 7. Because there are 2 electrons in the first orbital and 5 in the second and you still have space for 3 more. So it shares, 3 to get the stable octet. Therefore, there are 3 covalent bonds in N2.

Nucleic acids are polymers of individual nucleotide monomers.

Each nucleotide is composed of three parts:

a 5-carbon sugar,

a phosphate group, and

a nitrogenous base.

Calculation of molar mass of HNO3:

Atomic masses of H, N, O are 1, 14, 16 respectively

Now the molar mass of HNO3 is

HNO3 = 1X1 + 1X14 + 3X16

= 1 + 14 + 48

= 63 g/mol or amu.

A mixture is the blending of two or more dissimilar substances.

Characteristics of a Mixture:

1. It has No formula.

2. It is an impure sustance

3. They can be mixed in any ratio.

4. The properties of the mixture are the properties of its constituents.

5. Constituents can e easily seperated by physical methods.
eg: Heating, Drying, Crystallization, Distillation etc...

6. It is either homogenous or heterogenous.

A major characteristic of mixtures is that the materials do not chemically combine. Mixtures can be divided into those that are evenly distributed (homogeneous) and those that aren't (heterogeneous).

Mercury and Bromine both will be in liquid state at room temperature. But mercury is metal. Hence, bromine is the only non metal which is in liquid state at room temperature.