Question 1 A substance was analysed and was found to have a boiling point of 450 °C.
At room temperature it is a soft grey solid.
Which temperature could be the melting point of a pure sample of the substance?
A. -12 °C
B. 56 °C to 72 °C
C. 250 °C to 275 °C
D. 142 °C
[1 mark]

given the reactants, h2so4 and koh, we are asked to determine the product(s) of the reaction. since h2so4 is an acid and koh is a base. this is a neutralization reaction, thus, the products are salt and water. 

so, h+ from h2so4 will react with oh- from koh forming h2o. k+ will also react with so4 2- forming k2so4. therefore, the balanced reaction will be:

h2so4 + 2koh > k2so4 + 2h2o

explanation:

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.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)