Answer:
Scandium is the most reactive
 
        
             
        
        
        
Answer:
usage of trills and vibrato
Explanation:
earlier music used trills while later styles would use vibrato.
 
        
             
        
        
        
Answer:
Single Displacement reaction  
In a displacement reaction, a more reactive element replaces a less reactive element from a compound.
Change in colour takes place with no precipitate forms.	
Metals react with the salt solution of another metal.
Examples:
 2KI + Cl2 → 2KCl + I2 
CuSO4 + Zn → ZnSO4 + Cu 
Double displacement reaction
In a double displacement reaction, two atoms or a group of atoms switch places to form new compounds.
Precipitate is formed.
Salt solutions of two different metals react with each other.
Examples:  
Na2SO4 + BaCl2 → BaSO4 + 2NaCl
2KBr + BaCl2 → 2KCl + BaBr2 
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There are several ways of expressing concentration of solution. Few of them are listed below
1) mass percentage
2) volume percentage
3) Molarity
4) Normality
5) Molality
In most of the drugs, concentration is expressed either in terms of mass percentage or volume percentage. For, solid in liquid type systems, mass percentage is convenient way of expressing concentration, while for liquid in liquid type solutions, expressing concentration in terms of volume percentage is preferred. Present system is an example of liquid in liquid type solution 
Here, concentration of H2O2 is given antiseptic = 3.0 % v/v
It implies that, 3ml  H2O2 is present in 100 ml of solution
Thus, 400 ml of solution would contain 4 X 3 = 12 ml H2O2