When a metal reacts with a dilute acid, which products are typically formed in the chemical reaction?

Introduction / Context:
This question checks your understanding of basic inorganic reaction patterns, specifically the reaction between a metal and a dilute acid. Such reactions are standard in school chemistry and appear frequently in examinations and laboratory work. Knowing the general products of this reaction helps you predict what happens when metals are added to hydrochloric acid or sulphuric acid and explains observable effects such as effervescence due to gas release.

Given Data / Assumptions:

• Reactants: a metal and a dilute acid.
• Acids considered are typically dilute hydrochloric acid or dilute sulphuric acid.
• We assume that the metal is above hydrogen in the reactivity series so that the reaction actually proceeds.
• We are asked to identify the products formed.

Concept / Approach:
The general reaction of a reactive metal with a dilute acid is: metal + dilute acid → salt of the metal + hydrogen gas. For example, zinc reacts with dilute sulphuric acid to give zinc sulphate and hydrogen gas. The metal displaces hydrogen from the acid because the metal is more reactive than hydrogen. No chlorine is produced unless chlorine containing oxidising agents are used in a different type of reaction. Water is not the principal product in this simple displacement reaction.

Step-by-Step Solution:
Step 1: Recall the general form of the reaction: Metal + Dilute acid → Salt + Hydrogen gas. Step 2: Take a typical example. Zinc reacting with dilute sulphuric acid: Zn + H2SO4 (dilute) → ZnSO4 + H2. Step 3: In this reaction, ZnSO4 is the salt of zinc and sulphuric acid, and H2 is hydrogen gas. Step 4: Another example is magnesium reacting with dilute hydrochloric acid: Mg + 2HCl → MgCl2 + H2. Step 5: In all such reactions, the pattern remains the same. You always obtain a salt and hydrogen gas as the main products. Step 6: Therefore the correct description of the products is a salt and hydrogen.

Verification / Alternative check:
You can verify by remembering the reactivity series of metals. Metals above hydrogen in the reactivity series can displace hydrogen from dilute acids. The displaced hydrogen appears as hydrogen gas, which can be tested by the pop sound when a burning splint is brought near the mouth of the test tube. The remaining ionic part of the acid combines with the metal cation to form a salt. There is no mechanism in this simple displacement process to form chlorine gas, water, or a base as the main product.

Why Other Options Are Wrong:
Option A, a salt and chlorine, is incorrect because chlorine gas is produced from reactions involving oxidising chlorine compounds or electrolysis, not from simple metal acid reactions in school level examples. Option C, a salt and water, describes neutralisation reactions between acids and bases, not the reaction of acids with metals. Option D, a salt and a base, does not match any standard reaction type for metal with acid. Option E, only hydrogen, ignores the formation of the ionic salt, which is always produced in aqueous solution.

Common Pitfalls:
Students often confuse metal acid reactions with acid base neutralisation, where salt and water are formed. It is important to notice that in this question the second reactant is a metal, not a base. Another pitfall is to assume that any reaction involving hydrochloric acid and metals might produce chlorine gas, but at this level the standard pattern for such questions always emphasises hydrogen gas. Always check which species is being displaced from the acid, which is hydrogen in this case.

Final Answer:
When a metal reacts with a dilute acid, the typical products are a salt and hydrogen gas.