Answer: 
Explanation:
pH or pOH is the measure of acidity or alkalinity of a solution.
pH is calculated by taking negative logarithm of hydrogen ion concentration.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)

Putting in the values:

![5.29=-log[H^+]](https://tex.z-dn.net/?f=5.29%3D-log%5BH%5E%2B%5D)
![[H^+]=5.1\times 10^{-6}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D5.1%5Ctimes%2010%5E%7B-6%7D)
Thus ![[H^+]](https://tex.z-dn.net/?f=%5BH%5E%2B%5D) is
 is 
 
        
             
        
        
        
Answer:
Carboxylic acid
A carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is R−COOH or R−CO₂H, with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids.
 
        
             
        
        
        
The third one is correct, not sure abt another one
        
                    
             
        
        
        
The water on your skin is evaporating, pulling heat with it. This is  called evaporative cooling.
        
             
        
        
        
Answer:
The Standard Model of particle physics is the theory describing three of the four known fundamental forces (the electromagnetic, weak, and strong interactions, and not including the gravitational force) in the universe, as well as classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists around the world, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks.