Explain why small pieces of ice when pressed together from a single block. Name the phenomenon involved ?

Explain why a small piece of soap fixed to the back of a card board that is floating on water will cause it to move over the water surface.

Explain the development of a secondary oocyte (ovum) in a human female from the embryonic stage upto its ovulation. Name the hormones involved in this process.

(i) Write the balanced equations to represent what happens when (a) acidified potassium permanganates reacts with hydrogen sulphide ? (b) acidified potassium dichromate solution reacts with iron (II) solution (ionic equation) ? (ii) The figure given below illustrates the first ionisation enthalpies of first, second and third series of transition elements. (a) Which series amongst the first, second and third series of transition elements have the highest first ionisation enthalpy and Why ? (b) Why there is a fall in IE_(2) from Cr to Mn and from Cu to Zn ? Explain.

A piece of paper wrapped tightly on a wooden rod is found to get charged quickly when held over a flame compared to a similar piece of paper when wrapped on brass rod . Explain why ?