The liquids that produce effervescence (bubbling) when reacted with sodium carbonate solution are acids.

Here's why:

* Sodium carbonate (Na₂CO₃) is a base.

* Acids contain hydrogen ions (H⁺).

* When an acid reacts with a base, a neutralization reaction occurs, producing salt, water, and often carbon dioxide gas.

* Carbon dioxide gas is what causes the effervescence.

Examples of acids that react with sodium carbonate to produce effervescence:

* Hydrochloric acid (HCl)

* Sulfuric acid (H₂SO₄)

* Acetic acid (CH₃COOH) (found in vinegar)

* Citric acid (C₆H₈O₇) (found in citrus fruits)

The reaction:

```

Acid + Sodium Carbonate → Salt + Water + Carbon Dioxide

```

For example:

```

2 HCl (aq) + Na₂CO₃ (aq) → 2 NaCl (aq) + H₂O (l) + CO₂ (g)

```