can any one tell which one is an acid and which one is a base?

Question

a.) HNO2
B.)HCN
c.) Ca(OH)2
d.) CH3CO2H

Answer 1

The way to tell is if the equation has an "OH" molecule, or if it just has an "H" ion.

a.) we only see "H", so acid.

b.) we only see "H", so acid.

c.) we see "OH" (two of them, in fact!), so base.

d.) we only see "H", so acid.

Remember, too, that in pH scale, a high number (higher than 7) is basic, while any number lower than 7 is acidic. Pure water is exactly 7...makes sense since it is the perfect combination of both of the ions necessary to determine acidity: H + OH = H2O.

Answer 2

a - nitrous acid
b - hydrocyanic acid
c - slaked lime, a base
d - acetic acid (usually shown as CH3COOH)

Answer 3

a, b and d are acids, while c is a base.