Let's analyze the process described in the question: mixing ashes with animal fat. This combination is a key step in a very old method of creating a useful substance.

Understanding the Ingredients: Ashes and Animal Fat

Historically, ashes obtained from burning wood were important because they contain alkaline substances, primarily potassium carbonate (\(\text{K}_2\text{CO}_3\)) or sodium carbonate (\(\text{Na}_2\text{CO}_3\)). When these carbonates are dissolved in water, they form alkaline solutions (like lye).

Animal fat is a source of triglycerides. Triglycerides are esters formed from glycerol and fatty acids.

The Chemical Reaction: Saponification

Mixing an alkali (from the ashes) with fat leads to a chemical reaction called saponification. In this process, the alkali breaks down the triglycerides in the fat into glycerol and fatty acid salts. These fatty acid salts are what we commonly call soap.

The reaction can be simplified as:

\text{Fat (Triglyceride)} + \text{Alkali (from ashes)} \rightarrow \text{Soap (Fatty acid salt)} + \text{Glycerol}

When this process is done using crude ingredients like wood ashes and animal fat without much purification, the resulting substance is a crude form of soap.

Evaluating the Options

Let's look at the given options based on this understanding:

1. Pheromone: Pheromones are chemical signals released by animals that affect the behavior of others of the same species. This is unrelated to mixing ashes and fat.
2. Soap: As explained, mixing ashes (alkali source) with animal fat results in saponification, producing soap. The substance would be in a crude form if not purified further.
3. Cement: Cement is a binder substance used in construction, typically made from limestone, clay, and other minerals heated in a kiln. It is not produced from ashes and animal fat.
4. Concrete: Concrete is a composite material made from cement, aggregate (like gravel and sand), and water. It is a construction material and not related to the reaction of ashes and animal fat.

Based on the process of saponification, mixing ashes with animal fat produces soap in a crude form.

Comparison of Substances

Therefore, the substance received in crude form when mixing ashes with animal fat is soap.

Revision Table: Key Concepts

Additional Information: History of Soap Making

Soap making using animal fats and ash lye is an ancient practice with evidence dating back thousands of years. This method was the primary way to produce soap for cleaning until modern chemical processes were developed. The quality of the soap produced depended heavily on the type of ashes used (hardwood ashes generally yielding stronger lye) and the purity of the fat.

Modern soap making often uses purified alkali like sodium hydroxide (for bar soap) or potassium hydroxide (for liquid soap) and various fats and oils, followed by processes to purify the soap and add fragrances or other ingredients.