Which of the two \(Na^{ + }\) or \(Ag^{ + }\) is stronger Lewis acid and why?

Which of two : cuprous chloride or cupric chloride is coloured and why?

First ionisation energy of copper is higher than those of alkali metals, while second and third ionisation energies are lower. Explain.

Zinc is a transition element and has many useful applications. The presence of zinc in trace amounts is essential in humans and many animals.
Answer the following questions:
(i) What is the role of zinc in the body of humans and animals?
(ii) A compound of zinc is used as a rodent poison. Name the compound.
(iii) Name the compound of zinc used in paints.
(iv) Is \(ZnSO_{ 4 }(aq)\) coloured or colourless? 

The decomposition of potassium chlorate \((KCIO_{ 3 })\) is a slow process. But the decomposition becomes fast in the presence of a black powder.
Answer the following:
(i) Why does the use of black powder make the decomposition fast?
(ii) What is black powder?
(iii) Can the black powder be used for all decomposition reactions?
(iv) Can you name the substance which can slow down the decomposition of \(H_{ 2 }O_{ 2 }\) ?