A reagent bottle is labelled "Contains exactly of Formic acid ()". Which of the following prepared s — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question
Question
A reagent bottle is labelled "Contains exactly $23\text{ g}$ of Formic acid ($HCOOH$)". Which of the following prepared solutions would mathematically satisfy this condition? (Given: Molar mass of $HCOOH = 46\text{ g/mol}$, density of water = $1\text{ g/mL}$)
💡 Solution & Explanation
Evaluate each option for solute mass. A) Volume of sol = $46\text{ g} / 1.40\text{ g/mL} = 32.85\text{ mL}$. Mass of solute = $70\text{ g}$ per $100\text{ mL} \times 32.85\text{ mL} = 23.0\text{ g}$. (True). B) A $10\text{ M}$ sol ($d=1$) contains $10\text{ moles}$ ($460\text{ g}$) in $1000\text{ mL}$ ($1000\text{ g}$) of solution. Thus, $50\text{ g}$ of this solution contains $(460/1000) \times 50 = 23\text{ g}$. (True). C) $25\% \text{ w/w}$ of $50\text{ g} = 0.25 \times 50 = 12.5\text{ g}$. (False). D) A $5\text{ M}$ sol ($d=1$) contains $5\text{ moles}$ ($230\text{ g}$) in $1000\text{ g}$ solution. $46\text{ g}$ solution contains $(230/1000) \times 46 = 10.58\text{ g}$. (False).