Answer : The correct options are, 
and 
Explanation :
Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.
Option A reaction : 
It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.
Option B reaction :
It is an example of single displacement reaction.
Option C reaction : 
It is an example of combination reaction because in this reaction two reactants react to give a single product.
Option D reaction : 
It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.
Option E reaction :
It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.
Hence, the options B and E are single displacement reactions.
Answer: option (1) an electron.
Justification:
1) The plum pudding model of the atom conceived by the scientist J.J. Thompson, described the atom as a solid sphere positively charged with the electrons (particles negatively charged) embedded.
2) The next model of the atom, developed by the scientist Ernest Rutherford, depicted the atom a mostly empty space with a small dense positively charged nucleous and the electrons surrounding it.
3) Then, Niels Bhor came out with the model of electrons in fixed orbits around the nucleous, just like the planets orbit the Sun. So, the path followed by the electrons were orbits.
4) The quantum model of the atom did not place the electrons in fixed orbits around the nucleous but in regions around the nucleous. Those regions were named orbitals. And they are regions were it is most probable to find the electron, since it is not possible to tell the exact position of an electron.
As per this model, the electron has a wave function associated. The scientist Schrodinger developed the wave equation which predicts the location of the electron as a probability.
The orbitals are those regions were it is most likely to find the electron. Those regions are thought as clouds of electrons.
Answer:
Explanation:
Here, we want to get the equation of the reaction between Hydrochloric acid and Zinc metal
Zinc metal displaces the hydrogen from hydrochloric acid to form zinc chloride
We have the equation of reaction as:
Answer:
6.022 × 10²³ molecules of B₂H₆
Explanation:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
B₂H₆ molecules:
21.63 g = one mole of B₂H₆= 6.022 × 10²³ molecules of B₂H₆
