D. quantitative data can be recorded.
The pH a 0.25 m solution of C₆H₅NH₂ is equal to 3.13.
<h3>How do we calculate pH of weak base?</h3>
pH of the weak base will be calculate by using the Henderson Hasselbalch equation as:
pH = pKb + log([HB⁺]/[B])
pKb = -log(1.8×10⁻⁶) = 5.7
Chemical reaction for C₆H₅NH₂ is:
C₆H₅NH₂ + H₂O → C₆H₅NH₃⁺ + OH⁻
Initial: 0.25 0 0
Change: -x x x
Equilibrium: 0.25-x x x
Base dissociation constant will be calculated as:
Kb = [C₆H₅NH₃⁺][OH⁻] / [C₆H₅NH₂]
Kb = x² / 0.25 - x
x is very small as compared to 0.25, so we neglect x from that term and by putting value of Kb, then the equation becomes:
1.8×10⁻⁶ = x² / 0.25
x² = (1.8×10⁻⁶)(0.25)
x = 0.67×10⁻³ M = [C₆H₅NH₃⁺]
On putting all these values on the above equation of pH, we get
pH = 5.7 + log(0.67×10⁻³/0.25)
pH = 3.13
Hence pH of the solution is 3.13.
To know more about Henderson Hasselbalch equation, visit the below link:
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For plato users
the answer is a. O2(l) O2(g)
hope this helps!
Answer:

Explanation:
Given,
The density of Helium is 
We need to find the density in Dg/μm
We know that,
1 g = 10 dg
1 cm³ = 10¹² μm³
So,

So, the density of Helium is equal to
.
Answer:
a. 5.9 × 10⁻³ M/s
b. 0.012 M/s
Explanation:
Let's consider the following reaction.
2 N₂O(g) → 2 N₂(g) + O₂(g)
a.
Time (t): 12.0 s
Δn(O₂): 1.7 × 10⁻² mol
Volume (V): 0.240 L
We can find the average rate of the reaction over this time interval using the following expression.
r = Δn(O₂) / V × t
r = 1.7 × 10⁻² mol / 0.240 L × 12.0 s
r = 5.9 × 10⁻³ M/s
b. The molar ratio of N₂O to O₂ is 2:1. The rate of change of N₂O is:
5.9 × 10⁻³ mol O₂/L.s × (2 mol N₂O/1 mol O₂) = 0.012 M/s