<span>A.H2O = water, so it is a liquid at room temperatures (melting point = 0C) and melting point must be below 20C
B.HCl = A gas at room temperatures, so melting point (-114C) is definitely lower than 20C.
Melting points of the aqueous solution (solution in water) at different concentrations are all below that of water, i.e. 0C.
C.CH4 = A gas at room temperatures, so melting point (-182C) must be below 20C.
D.MgCl2 = A white powdery solid at room temperatures, so its melting point (714C) must be above 20C (So this is the only one among the four choices that melts above 20 ° C).</span>
When a compound containing C, H and O is completely combusted in air what reactant besides the hydrocarbon is involved in the reaction is Oxygen.
<h3>What is hydrocarbon?</h3>
A hydrocarbon is an organic molecule composed completely of hydrogen and carbon in organic chemistry. Group 14 hydrides include hydrocarbons. Hydrocarbons are often colourless and hydrophobic, with scents that are weak or exemplified by gasoline and lighter fluid. They exist in a wide range of molecular forms and phases, including gases (like methane and propane), liquids (like hexane and benzene), low melting solids (like paraffin wax and naphthalene), and polymers (such as polyethylene and polystyrene). Hydrocarbon refers to naturally occurring petroleum, natural gas, and coal, as well as their hydrocarbon derivatives and refined forms, in the fossil fuel industry. The primary source of energy on the planet is the combustion of hydrocarbons.
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Subtract the number of protons from the mass number.
