What two metals from the lanthanides of the activity series will not generate hydrogen gass when treated with an acid?

To determine which metals from the lanthanides of the activity series will not generate hydrogen gas when treated with an acid, we need to refer to the reactivity series of metals.

The reactivity series arranges metals in order of their reactivity with acids, with the most reactive metal listed at the top. In general, metals that are higher in the reactivity series will readily react with acids to produce hydrogen gas. However, metals that are lower in the reactivity series will either not react or will react very slowly with acids.

Unfortunately, the reactivity series of metals does not usually include the lanthanides specifically. However, we can infer their reactivity based on their position in the periodic table. The lanthanides are a group of elements located in the f-block of the periodic table, and they generally have similar chemical properties. They are also known to be less reactive compared to many other metals.

Given this information, we can assume that most lanthanides will not strongly react with acids to generate hydrogen gas. Therefore, it is not possible to identify two specific lanthanide metals that will not generate hydrogen gas when treated with an acid based solely on the reactivity series.

If you are looking for more detailed information about the reactivity of specific lanthanide metals with acids, you may need to consult specific scientific literature or databases that provide experimental data on the subject.