"Concentrated" nitric acid is only 70% pure. Obtaining anything stronger
than that becomes costly and the shelf-life declines markedly.
Sulphuric acid is commonly available (god knows why given the fact it's
used as a weapon nowadays in the black community) from BnQ., plumbers'
merchants and such like at concentrations of about 98% and you don't
really need anything stronger than that for general use.
Hydrochloric acid seems to top-out at only 36% purity and it's tough to
obtain any solution of it stronger than that.
Do we have any chemistry aces here who can explain the wide disparity in
the maximum strengths of these commonly available acids?