Answer:
Explanation:
The wavelength is the distance between two adjacent wavefronts. ... If the wave crosses to the new medium at an angle (not 90 degrees), the change ... When light enters a more optically dense medium, it is refracted closer to the normal. the same as the critical angle, light will travel along the boundary of the 2 mediums.

<h3><u>Basic </u><u>Characteristic </u><u>of </u><u>acids </u></h3>
- Acids are sour in taste
- Acid turns blue litmus paper or solution into red litmus paper or solution
- Acids are good conductor of electricity because it dissociate into cation in aqueous solution
- Acids classified into edible acids and non edible acids. Non edible acids are very hazardous
- Generally, All acids are soluble in water
- Acids have PH smaller than 7
<u>Arrhenius </u><u>definition </u><u>of </u><u>acids </u><u>:</u><u>-</u>
According to Arrehinus,
- Acids are those substances which when dissolve in water given H positive ions . Then, this hydrogen ions combine with water to form H30 + ions
<u>Second </u><u>definition </u><u>of </u><u>Acids </u><u>was </u><u>given </u><u>by </u><u>Bonsted </u><u>Lowry </u><u>:</u><u>-</u>
According to Bonsted Lowry
- Acids are the proton donors that is when acids dissociate into water gives hydrogen ions that is H+ ions
<u>3rd </u><u>definition </u><u>was </u><u>given </u><u>by </u><u>Lewis </u>
According to Lewis
- Acids are those substances which have the ability to accept a pair of electrons .
Example of Acids
- HNO3 :- Nitric acid
- H2SO4 :- Sulfuric acid
- HCl :- Hydrochloric acid
<h3><u>Basic </u><u>characterists </u><u>of </u><u>bases </u></h3>
- Bases are bitter in taste
- Bases turns red litmus paper into blue litmus paper or solution
- Bases are also good conductor of electricity because on dissociation it produces anion in aqueous solution
- Bases are also good conductor of electricity
- When bases are soluble in water then they are known as alkaline base
- Bases have PH greater than 7
<u>Arrehinus definition of bases :-</u>
According to Arrehinus ,
- Bases are those substances which when dissolve in water produce OH negative ions that is hydroxide ions
<u>Bonsted Lowry definition </u>
According to Bonsted Lowry
- Bases are the proton donors as they produce OH negative ions in dissociation in aqueous solution
<u>Lewis </u><u>definition </u>
According to Lewis
- Acids are those substances which have the ability to lose electrons that is they are electron donors.
Example of bases
- Ca(OH)2 :- Calcium hydroxide
- NaOH :- Sodium hydroxide
- KOH :- Potassium hydroxide
[ Note :- There are so many Lewis acids and bases but they are not Arrhenius or Lowry acids or bases ]
<h3><u>Basic </u><u>characteristic </u><u>of </u><u>salt </u></h3>
- Salts are the ionic compounds which are composed of acids and bases that cation and anion
- Salts are generally found in oceans and seas in the forms of crystals
- As they are composed of acids and bases so they are neutral in nature but the salt of strong acid or weak base is acidic in nature or vice versa
- Salts are also good conductor of electricity as they form ionic bond
- Generally, All salts are soluble in water.
- The PH of common Salt is 7
Example of salts
- NH4Cl :- Ammonium chloride
- CuSO4 :- Copper sulphate
- NaCl :- Sodium chloride
Answer:
The rusting of iron is spontaneous at low temperatures.
Explanation:
The given chemical reaction is:
4Fe(s) + 3O2(g) ----> 2Fe2O3(s) [rust]
The rusting of iron is a chemical reaction in which iron reacts with oxygen in presence of moisture and forms iron oxide.
This reaction takes place in a faster rate when there is low temperatures in the atmosphere.
When temperature is low, the moisture in the atmosphere is more and hence, rate of rusting is more.