In the triad of Li, Na and K, which will turn an aqueous solution of methyl orange-red and why?
The indicators which turn red in acid solution are :
(a) turmeric and litmus
(b) phenolphthalein and methyl orange
(c) litmus and methyl orange
(d) phenolphthalein and litmus
Among Li, Na and K, which will turn an aqueous solution of phenolphthalein pink and why?