When an iron nail is hammered, it becomes hot. Why?

When wire is bent back and forth, it becomes hot. Why?

The solutions of ZnSO4 , FeSO4, CuSO4 and AgNO3 are taken in four different test tubes. Suppose, an iron nail is kept immersed in each one: In which test tube the iron nail under goes a colour change?, What is the reaction taking place here?

When two liquids 'X' and 'Y' are mixed the solution becomes hot. When pair of liquids, 'Y' and 'Z' are mixed, the solution'becomes cold. Which of these SOLUTIONS will exhibit negative deviations from Raoult's law?

Tea or Coffee is sipped from a sáucer when it is hot. Why?

A student tries to plate an iron nail with copper. Draw its arrangement by selecting the required materials from the list given below. Silver nitrate, iron nail, copper sulphate, silver rod, copper rod, silver plate, iron sulphate, battery, wire, water, beaker.

Why iron rims are heated red hot before being put on the cart wheels?