Question

3. Consider "Like dissolves Like" Polar solutes dissolve in and solutes dissolve in nonpolar solvents. Compounds_ and ___ have bonds and are soluble in which is polar. Compound is not soluble in water but is soluble in nonpolar solvent called _so it has _bonds. Compound is soluble in water but does not electricity so it must have bonds joining some parts that are (polar, nonpolar) 4. Based on conductivity, a) Which of the unknowns are electrolytes? b) What type of bonding is present in the conductive unknowns? 5. Consider resistance (2) and conductivity. a) Resistance is to conductivity 1. Directly proportional ii. Indirectly proportional b) As ionic concentration increases, conductivity (increases or decreases) and resistance (increases or decreases)

these are the unknowns

Answer 1

3)

Polar solutes dissolve in polar solvents and nonpolar solutes dissolve in nonpolar solvents. Compounds B and C have polar bonds and are soluble in water which is polar. Compound D is not soluble in water but is soluble in nonpolar solvent called cyclohexane so it has nonpolar bonds. Compound A is soluble in water but does not conduct electricity so it must have nonpolar bonds joining some parts that are polar

Explanation:

Like dissolves like which means that compounds having polar bonds are soluble in polar solvents like water and they also tend to conduct electricity. On the other hand, compounds having nonpolar bonds are soluble in nonpolar solvents like cyclohexane and do not conduct electricity. But what is a solid dissolves in water but also does not conduct electricity (like sugar). Then it must be having mainly nonpolar bonds but some parts must be polar due to which it is soluble.

4) The unknowns which conduct electricity are called electrolytes. They are compound B and C. They have polar bonds which dissociates in water and they conduct electricity.

5)

a) Resistance is inversely proportional to conductivity. This is because, more an electrolyte resists electricity conduction lesser it conducts electricity.

b) Higher the concentration more is the conductivity due to more no. of free ions. Thus,

As ionic concentration increases, conductivity increases and resistance decreases