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<span>Carbonic acid is referred to as volatile acid because it is produced from a gas that evaporates quickly.
Volatility is the likeliness of a substance to vaporize. That is the tendency of the substance to pass to the gaseous phase. That means that these substances have a high vapor pressure. Coming from a gas, Carbonic Acid has a high tendency to pass to the vapor phase.
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The answer here is letter C. The optimal solution. The optimal solution is the one that affects how certain things changes with sensitivity analysis. The optimal solution is a feasibility solution where the objective function of it is to reach the minimum and maximum value.
One of the most important characteristic of a metal is its density. As density is the mass of any substance per unit volume. If one can measure the mass of the given shiny metal and its volume then the density of the metal can be determined. The density if matches with the density of the real gold then one can determine the metal is gold or not. The other experiments given will not work in any condition as-
1. Gold doesn't react with water.
2. The hardness of any metals are more than the non-metals and it is not at all an unique property of any metal.
3. All the metals usually reacts with acids or bases with more or less extent. thus it cannot identify the metal is gold or not.
4. The magnetic property is an inherent property of metal. There are several metals which shows magnetic property. Thus gold cannot be identified by this way.