Which substances are bases? check all that apply
a) hcooh
b) rboh
c) h2co3
d) ca(oh)2
e) nano3
f) hno3

The substances that are bases are

1. RbOH (answer B)

2. Ca(OH)2 (answer D)

explanation

A base is a substance that in aqueous  solution dissociate to give hydroxide ions (OH-)

RbOH  and Ca(OH)   are bases  since in aqueous solution they dissociate to release (OH-) ions according to below equations.

RbOH  → Rb+(aq)  + OH- (aq)

Ca(OH)2→  Ca2+ (aq) + 2OH- (aq)

8

explanation:

each principal energy level above the first contains one s orbital and three p orbitals. a set of three p orbitals, called the p sublevel, can hold a maximum of six electrons. therefore, the second level can contain a maximum of eight electrons - that is, two in the s orbital and 6 in the three p orbitals.

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the answers would be

the first one and the second one