which is more soluble in water? cyclohexane or glucose?

also out of propinoic acid or soidum propionate? and HCl or ethyl chloride? and why?

Solubility is typically enhanced when molecules are similar in structure/properties to the solvent. Water is a polar solvent with strong hydrogen bonding capabilities, and thus molecules which are polar (functional groups which enhance dipole moment) or ionic (e.g. salt, NaCl) or good hydrogen bond donors/acceptors (e.g. low molecular weight alcohols) tend to have high water solubility. So for these three cases:

1) Glucose, which has a high number of hydroxyl functional groups (-OH) relative to the number of carbons, is far more water soluble than cyclohexane. Cyclohexane, being completely hydrocarbon (Cs and Hs) and very non-polar has virtually no water solubility at all (hydrophobic; “greasy”)

2) Sodium propionate is more soluble than propionic acid. While the carboxylic acid (polar, hydrogen-bond capable functional group) of propionic acid can give it some water solubility, the sodium salt (sodium propionate) is more soluble, as the ionic character of the sodium carboxylate imparts huge water solubility enhancement relative to the “free acid”

3) HCl is more soluble than ethyl chloride. HCl is an ionic molecule, strongly polarized (H+ / Cl-). Ethyl chloride (CH3CH2Cl) is covalent, with a carbon chain (“greasy” hydrophobic, non-polar), and little dipole moment overall.

Hope that helps

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