Does `log_(2)0` exist ? Give reason .

Prove log_(b) 1=0

Sea water does not freeze at 0^(@)C .Give reason.

How does ionizatioin enthalpy vary along a period? Give reason.

Does self-incompatibility impose any restrictions on autogamy? Give reasons and suggest the method of pollination in such plants.

Name the type of quadrilateral formed, if any by the following points, and give reasons for your answer : (-1, -2), (1,0), (-1, 2), (-3, 0)

(a)Zr and Hf have almost identical radii : Give reason. (b)Name the gas liberated when Lanthanoids (Ln) react wtih acids.

A doctor prescribes a corrective lens of power -0.5 D to a person. Find the focal length of the lens. Is this lens diverging or converging? Give reason. How does the property of this lens can be used to correct eye defects ?

Are the following pair of sets equal ? Give reasons. A = {2, 3} , B = {x : x is solution of x^(2) + 5x + 6 = 0 }