Which of the following pairs are isoelectronic and isostructural?
$$NO_3^-$$, $$CO_3^{2-}$$, $$ClO_3^-$$, SO₃

Mixture X = 0.02 mol of [Co(NH₃)₅SO₄]Br and 0.02 mol of [Co(NH₃)₅Br]SO₄ was prepared in 2 litre of solution.
1 litre of mixture X + excess AgNO₃ $$ \to $$ Y.
1 litre of mixture X + excess BaCl₂ $$ \to $$ Z
No. of moles of Y and Z are

Which has maximum number of atoms?

If $$l\left( {m,n} \right) = \int\limits_0^1 {{t^m}{{\left( {1 + t} \right)}^n}dt,} $$ then the expression for $$l(m, n)$$ in terms of $$l(m+n, n-1)$$ is