At what temperature will the following reaction happen spontaneously, given that  δh  = 8.91×103  j/mol and δs  = –219.20 j/mol·k? caso4(s) + 2hcl(g) →  cacl2(s) + h2so4(l)

In order for a certain reaction to be spontaneous, the change in Gibb's free energy must be negative, that is:
dG < 0

We can calculate dG using:
dG = dH - dS

When we plug in the given values, we see that the sign of dG will never be negative; therefore, the reaction will not be spontaneous under any conditions.

8.7 degrees celsius and 15.6 degrees fahrenheit