Name two metals which will displace hydrogen from dilute acids, and two metals which will not.

Answer 

In displacement reactions, 

• Metals which lie above Hydrogen in the reactivity series can displace it from Dilute acids
• Those that lie below hydrogen in the reactivity series cannot .

Let’s look at the reactivity series:

Any of the metals in the series placed above Hydrogen can displace it from its acids. 

• Two such metals are - K (Potassium) and Na (Sodium)

Any of the metals in the series placed below Hydrogen will not be able to displace it from its acids. 

• Two metals which will not displace hydrogen are - Hg (Mercury) and Ag (Silver)