Hi, I kind of forgot how to solve for molarity, and I came across this question, but I checked the solutions, and, it didn't make sense. Could you help me with this question? Thank you!

Thanks Aditi
Check I have corrected it.

so the quiz I was talking about in class that wasn't working is , Quiz : 7.3 Atomic Spectra of Hydrogen and Bohr Model it shows error

Similar question we did in the class.
Now it is first order kinetics so we can use
ln[A]_t=-kt+ln[A]₀
You can rearrange this equation as
t = 1/k x  ln([A]₀/[A]_t
I discussed this format also.
[A]₀= 100 (assume because percent is given)
[A]_t= 1 (100-99)
k = 0.693/_t1/2 This we calculated in part i as 8ms
Just plug in all values and work out the answer as ms.

This reaction follows first-order kinetics because the half-life is constant throughout the process. By analyzing the graph, we can observe that the time required for the concentration to decrease from 1.60 M to 0.80 M is 8 ms. Similarly, the time required for the concentration to decrease from 0.80 M to 0.40 M is also 8 ms.

This constancy of half-life is a defining characteristic of first-order reactions. In first-order kinetics, the half-life is independent of the initial concentration, as expressed by the formula:
𝑡_1/2= 0.693/k

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k is the rate constant. Thus, the observation that the half-life remains unchanged at different concentration levels confirms that the reaction is first order.

I need help with parts i and ii 

Okay
I will check.

Thank you! However, the quiz is selecting the correct answer as 5.5. I just wanted to let you know so you could fix it later.

Your answer is correct.
In addition and subtraction ,follow the minimum decimal rule. So answer is 6 ⁰ C

Hi, I was redoing some quizzes to try to get higher scores when I found this problem. The initial temperature, as I have seen it to be, is around 22.5, and the final temperature is 28. 28-22.5 is 5.5, but since it is subtraction, shouldn't it be it be in minimum decimal places so that the correct answer is 6? Thanks, Siddharth.