Chemical reaction part 1

Difference between in Positive catalyst, Negative catalyst and Promoter

i.  Positive catalyst

     It is a catalyst which speeds up the rate of the reaction. 

     Examples: MnO2, V2O5, Pt 

  ii.  Negative catalyst

      It is a catalyst which reduces the rate of reaction. 

      Example: Alcohol 

  iii. Promoter 

      It is added to a catalyst to increase its efficiency. 

      Example: Molybdenum 

Difference between in Exothermic and Endothermic reaction

An exothermic process releases heat, causing the temperature of the immediate surroundings to rise.

An endothermic process absorbs heat and cools the surroundings.”

What are oxides and its types with examples

Oxides are a chemical compound with one or more oxygen atoms combined with other elements 

Types of oxides 

1) Acidic oxide: oxides are oxides of nonmetals.

example : $SO_2, CO_2 , SO_3$

2) Basic oxides: These are oxides of metals $CaO, MgO, Na_2O$

3) Amphoteric oxides: Which shows both basic as well as acidic properties. 

example  : $ZnO , Al_2O_3$

4) Neutral oxides: Shows  neither acidic nor basic properties 

example; $N_2O, NO, CO$

What is redox reaction? Give an example,why is the melting point of ice formed from tap water is below 0°c ? 

Answer:

Redox reactions are chemical reactions involving simultaneous reduction of one substance (gain of electrons) and oxidation of another substance (loss of electrons).

These reactions are always coupled.

One reactant undergoes oxidation and another is reduced.

An example :

Cl2 + 2KI -------> 2KCl + I2

Here Cl2 is reduced and KI is oxidized.

Tap water contains many impurities and minerals.

Presence of impurities in water makes it a simple solution. Such solutions undergo depression in freezing point/melting point.

As a result of this depression, tap water melts below 0°C.

What do you understand by redox reaction

Answer:

Those reactions in which both oxidation and reduction takes place is called redox reaction

Define chemical reaction

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products.

What are displacement reactions. give suitable examples