Which equation represents a correctly balanced chemical equation?

a. zn(s)+2hcl(aq)→2zncl2(aq)+h2(g)

b. 2zns(s)+2hcl(aq)→4zncl2(aq)+h2s(g)< br />
c. na2co3(s)→na2o(s)+2co2(g)

d. 4al(s) + 3o2(g) → 2al2o3(s)

i think its b. correct me if i am wrong. you.

The given degradation reaction of sodium carbonate is balanced equation. Option C is correct.

Balanced Equation:

It is the chemical equation in which the molar ratios are written correctly to balance consumed reactant and product that formed in the reaction.

For example-

Here, before the reaction, there are 2 sodium atoms, 1 carbon, and 3 oxygen atoms. After the reaction (In product), the number of atoms is also the same.

Therefore, the given degradation reaction of sodium carbonate is balanced equation.

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in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.