(20 1 1? Locks are common tools in daily life, among which iron locks (pictured) often rust. (1) When is the iron lock easy?

(1) Iron rusts easily in humid air or rain.

(2) Lock hooks are usually plated with other metals such as chromium and nickel to prevent rusting; The lock body is generally painted or the lock core is generally copper to prevent rust.

Therefore, fill in: ① Lock hooks are usually plated with chromium, nickel and other metals; ② The lock body is generally painted or the lock core is generally copper;

(3) Dilute hydrochloric acid can be used to remove rust, and the chemical equation of the reaction is: Fe2O3+6HCL = 2FeCl3+3H2O;

Therefore: fe2o 3+6h cl═2 FeCl 3+3h2o；;

(4) pencil lead powder (or vegetable oil, gasoline, lubricating oil or graphite powder) can be added into the lock core to make it rotate flexibly due to rust.

So: pencil lead powder.