Answer : The correct option is, (C) 2, 4 and 5.
Explanation :
Combustion reaction : It is a type of reaction in which a hydrocarbon react with an oxygen molecule to give carbon dioxide, water as a product.
For example : Methane react with oxygen to give carbon dioxide and water.

In the given list of chemical substances,
are in oxide form. They can not be both reactant and product of a single combustion reaction.
In the given list,
is the only hydrocarbon which shows a combustion reaction. That means
react with
to give
and
as a product.
The balanced combustion reaction of
is,

Therefore, the correct answer is, (C) 2, 4, and 5.
Answer:
Na has atomic number 11
which is less than magnesium has atomic number 12
ANSWER IS D
Explanation:
aluminum or Al is atomic 13 and Ca or calcium is atomic number 20 and rubidium or Rb is atomic number 37
Answer:
B. a strongly basic solution
Explanation:
Kb is base dissociation constant, which indicates how completely a base dissociates into its component ions in water. The greater the Kb value, the greater the alkalinity of the solution and vice versa.
Therefore, a solution with a Kb value much greater than 1, indicates a strongly basic solution, while a solution with a Kb value less than 1, indicates a weakly basic solution.
Answer:
its already in scientific notation form however its ordinary or real form is -0.005682
Explanation:
scientific notation
when a number is expressed with some power of 10 multiplied by a number between 1 to 10 is called scientific notation
oxygen is in gaseous state at this temperature