Why did Congress pass both the Missouri Compromise and the Compromise of 1850?

a. to permit states to secede from the Union under certain conditions

b. to maintain a balance of power between northern and southern states

c. to legalize slavery in all states and territories west of the Mississippi

d. to provide a legal means for the return of runaway slaves from Canada

Congress passed both the Missouri Compromise and the Compromise of 1850 to maintain a balance of power between northern and southern states. The correct option among all the options that are given in the question is the second option or option "b". Although both the northerners and southerners did not like all the clauses of the compromise, still they accepted them.