Which is an example of a chemical change

Answer : The correct option is, (C) metal corroding in salt water.

Explanation :

Chemical change : It is a change where changes occurs in the chemical composition and thus resulting in the formation of new compound or substance. It is an irreversible reaction.

The indication of chemical changes are :

Formation of gas bubbles.

Formation of precipitate.

Change in color.

Change in temperature.

Change in volume.

Change in smell or taste.

Evolution of heat, light and sound.

Physical change : It is a change in which shape and size of a substance changes. In this there is no change in the chemical composition of the substance and no new substance is forming. It is a reversible reaction.

The indication of chemical changes are :

Change in shape.

Change in form.

Change in size.

Change in phase.

(A) Mixing of poster colors : It is a physical change because only changes takes place in the phase from liquid phase to vapor phase.

(B) Formation of clouds : It is a physical change because only changes takes place in the phase from vapor phase to liquid phase.

(C) Metal corroding in salt water : It is a chemical change because the chemical composition of substance changes.

(D) Sugar dissolving in water : It is a physical change because only changes takes place in the phase from solid phase to liquid phase.

(E) Separating salt from seawater : It is a physical change because only changes takes place in the phase from liquid phase to solid phase.

Hence, the correct option is, (C) metal corroding in salt water.

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm