4.1 h = 14760 s
<span>t 1/2 = ln 2 / k </span>
<span>k = rate reaction = 4.97 x 10^-5 </span>
<span>ln 0.045 / 0.36 = - 4.97 x 10^-5 t </span>
<span>2.08 = 4.97 x 10^-5 t </span>
<span>t = 41839.9 s = 11 h 37 min 19 s</span>
Moles of potassium permanganate = 0.0008
<h3>Further explanation </h3>
Titration is a procedure for determining the concentration of a solution by reacting with another solution which is known to be concentrated (usually a standard solution). Determination of the endpoint/equivalence point of the reaction can use indicators according to the appropriate pH range
Reaction
5Na2C2O4(aq) + 2KMnO4(aq) + 8H2SO4(aq) ---> 2MnSO4(aq) + K2SO4(aq) + 5Na2SO4(aq) + 10CO2(g) + 8H2O(1)
The end point ⇒titrant and analyte moles equal
titrant : potassium permanganate-KMnO4
analyte : sodium oxalate - Na2C2O4
so moles of KMnO4 = moles of Na2C2O4
moles of Na2C2O4(mass = 0.2640 g, MW=134 g/mol) :

From equation, mol ratio Na2C2O4 : KMnO4 = 5 : 2, so mol KMnO4 :

Answer:
C. 1 proton 3 neutrons
Explanation:
A nucleus is more stable if the ratio of the neutrons to protons is between 1:1 and 1:1.5.
Thus the ratios of neutrons to protons for the nuclei are as follows
A- 1:1
B- 1:1
C- 1:3
D- 1:2
Among these ratios, C is the greatest thus the nucleus is the least stable.