Covalent for the first one
<span>The "p" in pH and pOH stands for "negative logarithm of" and is used to make it easier to work with extremely large or small values. pH and pOH are only meaningful when applied to aqueous (water-based) solutions. </span>
Stirring and agitating chemical reactions is desirable and stirring reflux systems or any system under heating is necessary to a distribute the heat evenly throughout the system and b) to prevent splashing and boilovers.
