rust is to iron as ___ is to silver
Not much to go on but I would guess perhaps silver oxide?
Rust is iron oxide.
I don't know if this is silver oxide -- but tarnish could also fit in that blank.
'patina' is the word for the discolouration on silver.
I haven't seen this question for over 30 years - definitely recycling!
To find the answer to this analogy, we need to identify the relationship between "rust" and "iron" and then find a similar relationship for "silver".
Rust is a form of iron oxide that occurs when iron reacts with oxygen and moisture. So, the relationship between "rust" and "iron" is that rust is a compound or an altered form of iron.
Now, we need to find something that is a compound or an altered form of silver. One such compound is "tarnish." Tarnish is a black or brown film that develops on silver when it reacts with sulfur compounds in the air. Therefore, the answer to the analogy "rust is to iron as tarnish is to" is "silver."
So, the completed analogy is: rust is to iron as tarnish is to silver.