In a chemical equation some arrow marks `rarr uarr darr`, are written. What do they indicate? Give examples.

Explanation

1) If a gas is evolved in a reaction, it is denoted by an upward arrow `darr.`
Eg : `Zn_((s))+H_(2)SO_(4(aq))rarr ZnSO_(4(aq))+H_(2(g))uarr.`
2) If a precipitation is formed in the reaction, it is denoted by a downward arrow, `darr`.
Eg : `AgNO_(3(aq))+NaCl_((aq))rarr AgCl_((s))darr +NaNO_(3(aq))`
3) The direction of reaction takes place is indicated by right side arrow `rarr` And also this arrow `(rarr)` separates reactants and products.
Eg : `C_((s))+O_(2(g))rarrCO_(2(g))+Q`
4) Hence, these arrows are giving useful information and simplifying the chemical reaction.