Question

Which two of the oxides (CO2, SiO, BeO, NO, ZnO) react neither with KOH nor with HCl?

Answer 1

`CO_2 and NO` most likely. A problem exists in the assumption of reaction conditions.

Explanation:

For example, both of these go through an intermediate form before the actual reaction. The `CO_2` forms carbonic acid/carbonates in water, and THOSE react with a base. The NO is undergoing an auto-redox into `NO_2 and N_2O` before reacting as well.
Carbon can form chlorides, but not by reacting with HCl.

The reaction mechanism of `SiCl_4` favors formation of an oxide, so the HCl reaction is unlikely. However, two possible reactions proceed with KOH.
`KOH + CO_2 → KHCO_3`
`2KOH + CO_2 → K_2CO_3 + H_2O` No reaction with HCl.

The following examples are not SiO, but it would be even more reactive than `SiO_2`
`6KOH + 5SiO_2 → K_4SiO_4 + K_2Si_4O_9 + 3H_2O`
`4KOH + 2SiO_2 → K_2SiO_3 + K_2Si_4O_5 + 2H_2O`
No reaction with HCl.

`BeO + 2KOH → K_2BeO_2 + H_2O`
`BeO + 2HCl → BeCl_2 + H_2O`

`ZnO + 2HCl → ZnCl_2 + H_2O` No reaction with KOH.
http://chemiday.com/

`2KOH + 4NO → 2K4NO_2 + N_2O + H_2O`
No reaction with HCl.
Potassium hydroxide reacts with nitric oxide to produce potassium nitrite, nitrogen dioxide and water. The reaction slowly proceeds at room temperature. http://chemiday.com/en/reaction/3-1-0-6770