Classify each of the following substances as either a strong or weak acid, strong or weak base, or a soluble or insoluble salt.
1. hclo4
2. pbcl2
3. koh
4. hno2
5. nabr
a. strong acid
b. weak acid
c. strong base
d. weak base
e. soluble salt
f. insoluble salt

KOH is a strong base, is a strong acid, is a weak acid, NaBr is a soluble salt and is an insoluble salt

Explanation:

According to solubility rule, all chlorides, bromides and iodides of metal ions are soluble except for and Hg^{+}[/tex].

Therefore NaBr is a soluble salt and is an insoluble salt.

There are seven strong acids : HCl, HBr, HI, , , and .

All group IA metal hydroxides e.g. NaOH, KOH etc. are strong base. Also, , and are strong bases.

So, KOH is a strong base, is a strong acid and is a weak acid.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.