Question

which symbol can be used to indicate a chemical reaction that takes place in the presence of a catalyst?
○ $xrightarrow{350^{circ}c}$
○ $xrightarrow{pt}$
○ $xrightarrow{0.5 atm}$
○ $xrightarrow{\triangle}$

Explanation:

In chemical reactions, the symbol of the catalyst (here Pt - platinum) is written above the arrow to indicate the reaction occurs in its presence. 350°C represents temperature, 0.5 atm represents pressure, and △ represents heat.

Answer:

Pt