Answer:
398 mL
Explanation:
Using the equation for molarity,
C₁V₁ = C₂V₂ where C₁ = concentration before adding water = 8.61 mol/L and V₁ = volume before adding water, C₂ = concentration after adding water = 1.75 mol/L and V₂ = volume after adding water = 500 mL = 0.5 L
V₂ = V₁ + V' where V' = volume of water added.
So, From C₁V₁ = C₂V₂
V₁ = C₂V₂/C₁
= 1.75 mol/L × 0.5 L ÷ 8.61 mol/L
= 0.875 mol/8.61 mol/L
= 0.102 L
So, V₂ = V₁ + V'
0.5 L = 0.102 L + V'
V' = 0.5 L - 0.102 L
= 0.398 L
= 398 mL
So, we need to add 398 mL of water to the nitric solution.
Answer : The correct option is, (b) +115 J/mol.K
Explanation :
Formula used :

where,
= change in entropy
= change in enthalpy of vaporization = 40.5 kJ/mol
= boiling point temperature = 352 K
Now put all the given values in the above formula, we get:



Therefore, the standard entropy of vaporization of ethanol at its boiling point is +115 J/mol.K
It is reflected ir transmitted depending on what the material is. The color that something appears is actually the color that it reflects or transmits and not the color that it absorbs. I hope this helps.
We have to fill the gap
The correct answer is: Metals with the largest atoms and the smallest number of valence electrons and non-metals with the smallest atoms and the greatest number of valence electrons are the most reactive.
Reactivity of any species depends on ease of release or gain of electron. The species which can release electron easily from valence shell, the species is more reactive whereas the species which can accept electron to its valence shell easily is also more reactive.