What is corrosion? Why aluminium sheets do not corrode easily? Write two necessary conditions for corrosion to take place.

State necessary condition of iron corrosion.

List two conditions necessary for the imbibition to take place.

Two particles A and B are projected simultaneously in a vertical plane as shown in figure. They collide at time t in air. Write down two necessary equations for collision to take place.

Define an isothermal process and state two essential conditions for such a process to take place.

What are the two necessary conditions for the colliding molecules to yield the products ?

State the conditions necessary for a chemical change or reaction to take place.

Define rusting. What are the two necessary conditions for rusting of iron ? Give the chemical name of rust.

What do you mean by a nucleotide ? Write two functions of DNA.

Why are certain compounds called hydrocarbons? Write the general formula for homologous series of alkenes and alkynes and also draw the structure of the first member of each series. Write the name of the reaction that converts alkenes into alkanes and also write a chemical equation to show the necessary conditions for the reaction to occur.

Two point electric charges of unknown magnitudes and signs are placed a certain distance apart. The electric field intensity is zero at a point not between the charges but on the line joining them. Write two essential conditions for this to happen.