I’m not sure but it has to be hydrogen
Answer:
The heat of the solution of salt is 1.66.11 J/g.
Explanation:
Mass of the water = m = 46.52 g
Initial temperature of the water = 
Final temperature of the water = 
The specific heat of water, c = 4.180 J/gºC
Heat associated with water on dissolving salt: q



Negative sign means that heat was lost by water on an addition of a salt.
Heat released on dissolving of salt = -Q = 748.65 J
Mass of salt added = 4.5069 g
Heat of the solution of salt :
= 
The heat of the solution of salt is 1.66.11 J/g.
i believe the answer is B: both wind up at 60°C
but it's also reasonable to assume, given enough time, they wind up at 20°C because the water would heat up to cool the metal then slowly release the heat to the air untill they both reach 20°C
if it were me I'd answer B, apologies if I'm wrong