Answer:
two valence electrons
Explanation:
Magnesium is alkaline earth metal and belongs to group IIA of the periodic table. It has two valence electrons which are present in 3s subshell.
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Answer: 0.422 M⁻¹s⁻¹
Explanation: <u>Reaction</u> <u>Rate</u> is the speed of decomposition of the reactant(s) per unit of time.
A <u>Rate</u> <u>Law</u> relates concentration of reactants, rate reaction and rate constant:
![r=k[A]^{x}[B]^{y}](https://tex.z-dn.net/?f=r%3Dk%5BA%5D%5E%7Bx%7D%5BB%5D%5E%7By%7D)
where
[A] and [B] are reactants concentration
x and y are reaction order, not related to the stoichiometric coefficients
k is rate constant
r is rate
Before calculating rate constant, first we have to determine reaction order.
In this question, the reactio order is 2. So, the rate law for it is
![-\frac{d[A]}{dt} =k[A]^{2}](https://tex.z-dn.net/?f=-%5Cfrac%7Bd%5BA%5D%7D%7Bdt%7D%20%3Dk%5BA%5D%5E%7B2%7D)
and the integrated formula is
![\frac{1}{[A]} =\frac{1}{[A]_{0}} +kt](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B%5BA%5D%7D%20%3D%5Cfrac%7B1%7D%7B%5BA%5D_%7B0%7D%7D%20%2Bkt)
in which
[A]₀ is initial concentration of reactant
Then, using initial concentration at initial time and final concentration at final time:



k = 0.422
The rate constant for the reaction is 0.422 M⁻¹.s⁻¹
The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve. Hence, option A is correct.
<h3>What is a weak acid?</h3>
Weak acids are acids that don't completely dissociate in solution.
A weak acid is an acetic acid. It has a of 1.8⋅
. Calculate how much it will dissociate in water. Since acetic acid is a weak acid so large part will not dissociate completely.
![k_a=\frac{[CH_3COO^-]H^+]}{[CH_3COOH]}](https://tex.z-dn.net/?f=k_a%3D%5Cfrac%7B%5BCH_3COO%5E-%5DH%5E%2B%5D%7D%7B%5BCH_3COOH%5D%7D)
B is not true, it shows the titration curve for weak/strong acid titrated with a strong base. When choosing an indicator for colourimetric titration select one so that the pH jump at the equivalence point contains the interval p±1. Phenolphthalein has a p≈9, so to decide if it is a suitable indicator check if the pH jumps from 8 to 10 at the equivalence point.
C is not true either because of the very slow reaction.
Learn more about weak acid here:
brainly.com/question/12811944
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