Liquid is one of the three primary states in which matter exists around us. In our daily life, we come across several liquids that we generally either categorize as a pure liquid or a mixture. The most abundant liquid present on our planet earth is water. Most of the water present on earth is not pure but a mixture of various dissolved substances. We can often tell the difference between impure and pure liquids just by looking at the visibly separable solid impurities suspended in them. However, for the liquid impurities, the situation becomes entirely different as many pure liquids can easily mix to form a mixture. The degree to which one liquid can mix with another is associated with the term called “miscibility.” It is a property of two liquids to mix in all proportions to form a homogeneous mixture. The fewer the degree of miscibility, the less likely are the two liquids to mix. For instance, water and oil produce a mixture of two immiscible liquids, whereas water and ethanol produce a mixture of two miscible liquids. Miscibility of two materials is often determined optically. When the two miscible liquids are combined, the resulting liquid is clear. If the mixture is cloudy, the two materials are immiscible. Care must be taken with this determination. If the indices of refraction of the two materials are similar, an immiscible mixture may be clear and give an incorrect determination that the two liquids are miscible.
1. Acetic Acid and Water
Vinegar is a sour liquid that we use to add flavor to several dishes. It is most commonly used to prepare salad dressings. Vinegar is chemically known as an aqueous solution of acetic acid that is made by the fermentation of any of numerous dilute alcoholic liquids. Vinegar comprises a 5-8% aqueous solution of acetic acid homogeneously mixed with trace amounts of several flavorings. The fruit juices, mainly from grapes and apples, or any other liquid that can be converted into alcohol in a two-step process can yield a solution of acetic acid and water by the action of yeast enzymes and atmospheric oxygen. Vinegar is primarily used in culinary arts; however, it is also one of the very few edible items that can also be used for cleaning purposes.
2. Gasoline (Petrol) and Deisel
Gasoline and diesel are two different types of liquid hydrocarbon fuels that are derived from another naturally occurring fossil fuel known as petroleum or crude oil. Petroleum is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e., separation of a liquid mixture into fractions, differing in boiling point through distillation, typically using a fractionating column. Both gasoline and diesel fuel consist of hundreds of different hydrocarbon molecules. Although petrol (gasoline) and diesel fuels are two miscible liquids that can mix readily, it is generally advised not to mix them as fuel for the vehicle as it may cause problems with the emissions reduction systems of the modern vehicles, causing their engine or exhaust to choke up on smoke. However, the mixture certainly will not cause any physical damage outside the engine.
3. Milk Coffee
Most people around the world enjoy coffee and its ability to provide a boost of instant energy. While some people like to have black coffee, others prefer to have milk coffee. There are approximately 28 different kinds of coffee beverages that can be prepared by mixing two miscible liquids, milk and an aqueous solution of coffee. Most of the varieties of milk coffee are prepared by homogeneously mixing coffee solution and milk. One of the most famous of these varieties is espresso coffee, which is prepared by mixing steamed milk in a 1:1 ratio with an aqueous solution of coffee. However, there are also some varieties such as latte, which are prepared as a homogeneous solution of just coffee and milk.
4. Lemonade
Lemonade is a sweet lemon-flavored beverage that is most commonly consumed in summers to deal with quenching thirst and loss of necessary electrolytes from the body. It is a vitamin C rich beverage that is made by thoroughly mixing lemon juice with water and little amount of sugar. The proportions vary depending on how much sweet and strong you like your lemonade. There are varieties of lemonade found throughout the world. Also, many brands sell a packed lemon-flavored carbonated beverage such as Schweppes and R. White’s Lemonade.
5. Mocktails
Mocktails are a mixture of non-alcoholic beverages that are enjoyed primarily by people who do not like to drink alcohol. The word “mocktail” is an abbreviation for “mock cocktails” and implies a facade of the alcoholic cocktail without any of the alcoholic content in them. Mocktails can be described as a smooth blend of only non-alcoholic drinks, which could be fresh fruit juices, syrups, cream, herbs, and spices. They are particularly favored over cocktails by drivers, pregnant women, and others who choose alcohol-free festive drinks. However, not all mocktails can be generalized as a mixture of miscible liquids. Some mocktails may include fruit pulp or any other solid ingredients, which will then make a suspension and not a homogenous liquid mixture.
6. Distilled Liquor
Liquor is a generic designation given to a recreational alcoholic beverage around the world. While buying a bottle of liquor, a customer determines its potency by the V/V or W/W label present on the bottle. This label tells the ratio of the alcohol content to the water. For instance, 42.8% V/V is a measure that 42.8 ml of alcohol is mixed with 100 ml of water. The distilled liquor that is sold over the counter is basically a homogenous mixture of two miscible liquids: alcohol and water. The composition of water and alcohol remains the same throughout the bottle. Examples of distilled liquors include brandy, vodka, baijiu, shōchū, soju, gin, rum, tequila, mezcal, and whisky.
7. Cocktails
A cocktail is usually a blended drink made with a distilled liquor as its base ingredient (such as arrack, brandy, cachaça, gin, rum, tequila, vodka, or whiskey) that is then mixed with other ingredients or garnishments. Sweetened liqueurs, wine, or beer can also be added or served as the base. The beverage is called a beer cocktail if beer is one of the ingredients. Cocktails often also contain one or more types of juice, fruit, honey, milk or cream, spices, or other flavorings. Cocktails, like everything else in this world, cycle through trends. Cocktails may vary in their ingredients from bartender to bartender, and from region to region. Two creations may have the same name but taste very different because of differences in how the drinks are prepared. Even among the classics, drinker’s preferences change in often unexpected ways.
8. Wine
Wine is an alcoholic beverage generally made of grape juice. For thousands of years, wine has played a significant role in many cultures, starting with the oldest-known winery in Armenia discovered in 4100 B.C. through the Greek, Roman, and Egyptian empires up to today. The grapes from vineyards are fermented with mainly two ingredients, sugar and yeast, to produce a homogenous solution of ethanol and water called wine. Yeast consumes the naturally occurring sugars in the grape juice to releases three components: ethanol, {CO}_{2}, and heat. The {CO}_{2} and heat escape and the ethanol remain. Different varieties of grapes and strains of yeasts produce different styles of wine. Many countries enact legal appellations intended to define styles and qualities of wine.