Answer:
He will decide which drink is to be served to whom, by the use of litmus paper.
Explanation:
The litmus paper is the most common indicator to determine the acidity or basicity of a solution. Blue litmus paper changes its color to red when a solution changes from basic to acidic while red litmus paper changes its color to blue when the opposite occurs (acid → basic).
First of all the litmus paper strip, pH indicator, is immersed in a solution and allowed to pass between 10 and 15 seconds while keeping the strip submerged. Afterwards it is removed, and then the strip compares the color. If the color is diffuse, there is a color scale where it is determined which solution has alkaline or acidic pH
Answer:
hypothesis
Explanation:
a question that can be answered wity a hypothesis is a question a scientist can answer
Lower fertility and longer lifespans steadily increased the potential labor force relative to the total population
Answer:
3) NaCl.
Explanation:
<em>∵ ΔTf = iKf.m</em>
where, <em>i</em> is the van 't Hoff factor.
<em>Kf </em>is the molal depression freezing constant.
<em>m</em> is the molality of the solute.
<em>The van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass. </em>
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- For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.
<em>So, for sugar: i = 1.</em>
<em>∴ ΔTf for sugar = iKf.m = (1)(Kf)(2.0 m) = 2 Kf.</em>
<em></em>
- For most ionic compounds dissolved in water, the van 't Hoff factor is equal to the number of discrete ions in a formula unit of the substance.
For NaCl, it is electrolyte compound which dissociates to Na⁺ and Cl⁻.
<em>So, i for NaCl = 2.</em>
<em>∴ ΔTf for NaCl = iKf.m = (2)(Kf)(1.0 m) = 2 Kf.</em>
<em></em>
<em>So, the right choice is: 3) NaCl.</em>
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