Generally speaking the solvent will be the one you have the most of (unless otherwise specified) and the solute is the one you have the least of. When using the karat system in gold, the total of the mixture is always 24 So 24 karat gold is pure gold 18 karat gold means 18 parts gold and 6 parts rest of the alloy 10 karat gold means 10 parts gold and 14 parts rest of the alloy So for 10 karat gold the is more alloy than gold, which makes the alloy the solvent and the gold the solute. I’m afraid I don’t know what the other metals in the alloy are.. EDIT:::::::::::::::::::::::::::: A solution refers to a homogeneous mixture of 2 or more substances. They can be in any phase.