Answer:
pH = 2.0
Explanation:
To find the pH of a solution, take the -log[H+]. In this case, the -log(9.4 x 10^-3) equals 2.02687 which makes 2.0 when accounting for significant figures.
I'm happy to help but do you have the options?
The two dimensions of aluminum foil are given 13.72 cm and 8.63 cm respectively with mass 3.1 g.
The density of aluminum is
. It is defined as mass per unit volume thus, volume of aluminum can be calculated as follows:

Putting the values.

The volume of cuboid is
, the length and breadth are given, height can be calculated as follows;

Putting the values,

Or, approximately 9.7\times 10^{-3}cm
Therefore, thickness of aluminum foil is 
Answer:
B. K+cation
Explanation:
Not all that sure but hope it will help.
Answer:
D
Explanation:
Firstly it is pertinent to know that, Electric force are due to the movement of electrons that is due to its gain and loss. This phenomenon is based on static electricity.
When the glass ruler is rubbed over the woolen sweater, the wool gets positively charged and the ruler gains electron to form negative charge.
Now if this charged is not earthed, the negative charged ruler attracts the uncharged bits of paper, as a result of which the paper gets attached to the ruler.