Magnetism, or more specifically electromagnetic repulsion
Here's link to the answer:
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Answer :
The time taken by the reaction is 19.2 seconds.
The order of reaction is, second order reaction.
Explanation :
The general formula to determine the unit of rate constant is:

Unit of rate constant Order of reaction
0
1
2
As the unit of rate constant is
. So, the order of reaction is second order.
The expression used for second order kinetics is:
![kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}](https://tex.z-dn.net/?f=kt%3D%5Cfrac%7B1%7D%7B%5BA_t%5D%7D-%5Cfrac%7B1%7D%7B%5BA_o%5D%7D)
where,
k = rate constant = 
t = time = ?
= final concentration = 0.97 M
= initial concentration = 2.48 M
Now put all the given values in the above expression, we get:


Therefore, the time taken by the reaction is 19.2 seconds.
The answer is c.
Elements on the left side of the table are metals, such as sodium, lithium, potassium, etc.
Elements on the right side are non metals, such as Chlorine, Fluorine, Bromine, etc.
The reaction between K₂SO₄(aq) and SrI₂(aq) produces KI(aq) and SrSO₄(s) as products.
The reaction is
K₂SO₄(aq) + SrI₂(aq) → KI(aq)+ SrSO₄(s)
To balance the equation both side of the reaction should have same number of atoms in each element.
Right hand side of the reaction has 1 K, 1 I, 1 Sr, 1 S and 4 O atoms while 2 K, 2 I, 1 Sr,1 S and 4 O present in left hand side of the reaction.
Hence, number of I atoms and number of K atoms are not balanced.
To balance the K atoms we should add 2 before KI. Then I atoms will be 2 at the right hand side.
Hence, the balanced reaction equation is
K₂SO₄(aq) + SrI₂(aq) → 2KI(aq)+ SrSO₄(s)