Which of the following equations depicts a balanced equation, na2co3+2hcl=2nacl+co2+h2o, naco3+hcl=2nacl+co2+1h2o, 2na2co3+3hcl=3nacl+2co2+h2o or na2co3+hcl=nacl+co2+h2o? ?

Option A is the Answer

Explanation:

Balancing is making the number of atoms of each element same on both the sides  (reactant and product side).

To find the number of atoms of each element we multiply coefficient × subscript  

For example contains  

5 × 1 = 5 , Ca atoms and

5 × 2 = 10, Cl atoms  

If there is a bracket in the chemical formula  

For example we multiply coefficient × subscript × number outside the bracket.......... to find the number of atoms  (Please note: 3 is the coefficient, and if there is no number given then 1 will be the coefficient )

So 3 × 3 = 9, Ca atoms  

3 × 1 × 2 = 6, P atoms  

3 × 4 × 2 = 24, O atoms are present.

A)

Reactant Side       # of atoms of each element      Product Side

2                                            Na                                      2

1                                             C                                        1

3                                             O                                       3

2                                             H                                       2

2                                             Cl                                       2

Balanced

B)

(Chemical formula given for Sodium carbonate  is not correct)

Na2CO3 is the correct formula

C)

(Not balanced correctly)

Reactant Side       # of atoms of each element      Product Side

4                                            Na                                      3

2                                             C                                       2

6                                             O                                       5

3                                             H                                       2

3                                             Cl                                      3

Not same on both the sides

Hence  UnBalanced  

D)

Unbalanced

answer: they produce more slow than unicellular organisms.