Final answer:
Many transition metals react with acids to form salts and release hydrogen gas. Noble metals are exceptions and do not readily react with acids. The reactivity towards acids mainly depends on the metal's oxidation state and position in the activity series.
Step-by-step explanation:
Not all transition metals dissolve in acids. While many transition metals do react with acids to form salts and hydrogen gas, there are exceptions such as noble metals which include gold, silver, and platinum, and do not react with most acids. Transition metal oxides with low oxidation states generally react with acids as they are basic, whereas those with intermediate oxidation states are amphoteric and can react with acids or bases.
The highest oxidation state oxides are often acidic and insoluble in water. A common reaction involves acids such as hydrochloric acid reacting with a transition metal like chromium to form a solution of the metal chloride and hydrogen gas, indicative of the metal's ability to act as a reducing agent.
For example, the reaction between chromium metal and hydrochloric acid can be represented as:
Cr(s) + 2HCl(aq) → CrCl₂ (aq) + H₂(g).
The ability to dissolve in acids is often linked to the metal's position in the activity series; transition metals above hydrogen in the series will react with acids. The solubility of transition metal compounds like halides and formation of complex ions also showcases the flexibility of transition metals to form various stable oxidation states.