In this case, the undergoing chemical reaction is:
Thus, the rate is given as:
It is necessary to remember that each concentration to time interval is divided into the stoichiometric coefficient, that is why HBr has a 1/2. Moreover, the concentration HBr is negative since it is a reactant and it has a negative rate due to its consumption.
The critical temperature of a substance is the temperature at and above which vapour of the substance cannot be liquefied, no matter how much pressure is applied.
Answer: In polar covalent bonds a pair of electrons are unequally shared between two atoms, while in nonpolar covalent bonds two atoms share a pair of electrons with each other.