多用途的蘇打粉：從烘焙到清除塗鴉 The Versatile Baking Soda: From Baking to Graffiti Cleaning 13 What is Baking Soda? Baking soda, scientifically known as sodium bicarbonate (NaHCO3), can be found in almost every household counter. Despite its name, most people keep baking soda in their homes not because of their baking passion, but due to its wide applications. Sodium bicarbonate is a weak base that has an alkaline pH range of eight to nine when dissolved in water. This article will explore some uses of baking soda within and beyond your home. Baking Fluffy Pastries In baking, sodium bicarbonate serves primarily as a leavening agent [1, 2]. When reacted with the acidic ingredients in a recipe — such as cream of tartar, lemon juice, or yogurt — baking soda undergoes an acid-base reaction to produce carbon dioxide gas, causing the dough or batter to rise and create the fluffy texture of baked goods. The acid-base reaction alone can take place at room temperature, but sodium bicarbonate also undergoes thermal decomposition at temperatures above 50°C to produce extra carbon dioxide (table 1). However, it is crucial to strike a balance between the amount of acid and base in a recipe. An excess of baking soda can lead to a bitter and metallic taste due to the unreacted sodium bicarbonate. In fact, a product called baking powder aims to ease this task, as it consists of both sodium bicarbonate and powdered acids already mixed in a right proportion [1]. Combating Foul Smell from Trash Bin Another handy household application of baking soda comes from its ability to neutralize odors. The offensive smells produced by the anaerobic decomposition of organic waste in your trash bin can be attributed to volatile fatty acids and ammonia [3, 4]. A study found that spreading 50 grams of baking soda at the bottom of an eight-liter food waste bin could reduce odors by 70% [3]. Baking soda can mitigate the unpleasant odors by neutralizing odor-producing acids, turning the volatile acids into involatile salts [5]. For example, as a volatile acid with a boiling point of 164°C [6], the vaporization of a small portion of butyric acid can already give an odor like rancid butter. Sodium bicarbonate can neutralize the acid to sodium butyrate, a solid with a melting temperature of 250°C, so it will require a much higher temperature to vaporize [7]. This simple method showcases the practicality of By Daria Zaitseva Acid-base reaction: NaHCO3(s) + H+(aq) → Na+(aq) + CO2(g) + H2O(l) Thermal decomposition: 2 NaHCO3(s) ⇌ Na2CO3(s) + CO2(g) + H2O(l) Table 1 The two reactions of sodium bicarbonate that produce carbon dioxide during baking.
RkJQdWJsaXNoZXIy NDk5Njg=