...the idea that sulfuric acid [presently, or recently] played or plays a part
in the formation of certain martian geological features [crater gullies?]
and geological oddities [Hematite spherules] just doesn't hold up
when certain facts are taken into account.

For instance!
(1) Pure or nearly-pure sulfuric acid has a melting-point of
about [10 degrees Centigrade] 50 degrees Fahrenheit.
I checked the CSDS website to confirm this!

(2) Mars is for the most part much colder; near pure H2S04 would freeze solid.
[Only during the martian summer, around martian high-noon, near the equator do temperatures
briefly approach the H2S04 MP.]

(3) HCL [pure hydrochloric acid] does have a much lower melting-point, close to
-100 degrees Centigrade, but it's hypothetical presence on Mars would be problematic
and unlikely to be present on Mars in any appreciable quantities.

(4) A more likely hypothesis for present-day martian regents would be highly saline-water and acid mixtures
that do have very low melting-points, and would remain liquid, or at least a pasty sludge,
in average martian daytime conditions [-40 Centigrade temeratures?; 0.7 millibars pressure]

Sorry to be a bit of a [pardon the pun] a 'wet blanket'.

Jacob

"Extraordinary claims, require extraordinary evidence."
CARL SAGAN