## Define molarity, molality, normality, mole-fraction.

Molarity (M):  Molarity is defined as the number of moles of solute per litter of solution. That is, Here,     W = weight of solute.     M = molecular mass of solute     V = volume of solution Molality (m):   It is defined as the number of moles of solute per kg of solvent. … Read more

## Show that the half-life of a second order reaction is inversely proportional to its initial concentration.

For the simple second order reaction 2A→product, we know the rate constant is given by, For half life,  and  Hence, as k is a constant, Thus, the half life of a second order reaction is inversely proportional to its initial concentration.

## Derive an expression for the rate constant of 2nd reaction of the type, 2A→product.

2A → Productinitial concentration : a molL-1                       →                              0final concentration (t=t) : (a-x) molL-1             →                  x … Read more

## Derive an expression for the rate constant of a first order reaction. Give its units.

Let us consider a first order reaction, A → product Suppose at the beginning of the reaction, that is, when t=0, the concentration of A is amolL and when t=t, the concentration of A is (a-x)molL. For a first order reaction, the rate of reaction, where k is the rate constant. integrating, Here, c is the … Read more

## Define order and molecularity.

Order: Order of a reaction is defined by the number of atoms or molecules, whose concentration change during the reaction and determine the rate of the reaction. For example, It is a first order reaction. It is a second order reaction. Molecularity: The molecularity of an elementary reaction is defined as the number of reactant … Read more

## Explain an example of Dry Cell or Short note on Leclanche cell.

Example of Dry Cell – Leclanche Cell: The most common example of dry cell is Leclanche cell invented by French scientist Georges Leclanche. We use to call it a battery. It has a cylindrical Zn container which works as the anode. At the center of the Zn container a carbon or graphite rod is placed … Read more

## What is chemical bond? What are different types of chemical bonds?

Chemical bond Atoms of all elements except of the inert gasses have a tendency to combine either with each other or with the atoms of other elements to form cluster of atoms with definite composition. A cluster formed may be either a molecule or an ion. The attraction between the atoms forming the cluster is … Read more

## Nature of bonding and properties of certain solids.

Diamond Diamond is an allotrope of carbon. Due to difference in bonding in its structure, it looks quite different from the other allotropes. Each carbon atom of diamond is sp3 hybridized. The four sp3 orbital arrange themselves in the four corners of a tetrahedron. Each orbital forms a bond with an orbital of another carbon … Read more

## Briefly explain the formation of dimmers and trimmers.

Some compounds like hydrogen fluorides, ethanoic acids, benzoic acid form dimmers or trimmers by joining up of their two or three molecules by H-bonding. Sometime, due to the formation of these dimmers or trimmers the molecular weight of these compounds appears to be doubled or tripled. That is, ethanoic acid has molecular weight of 60, … Read more

## Briefly explain Atomic spectra and Hydrogen Spectra.

Atomic spectra: When a ray of light is passed through a glass prism, it is dispersed into a band of seven colors. This is called a spectrum.  When a gas or vapor is heated to a high temperature or subjected to electric discharge, it emits light of all wavelengths. This light, if passed through a … Read more