Which one of the following is not a mixture ?

In chemistry, a mixture consists of two or more substances mixed together that retain their individual properties and do not react chemically [2]. Baking soda is the common name for sodium bicarbonate (NaHCO3), which is a pure chemical compound. A pure substance consists of the same type of particles and can be either an element or a compound [2]. In contrast, toothpaste is a complex mixture containing various ingredients like sodium fluoride, abrasives, and flavorings. Toilet soap is a mixture of fatty acid salts and additives. Vinegar is a mixture, specifically a dilute solution of acetic acid in water. Therefore, while toothpaste, soap, and vinegar are formulations or solutions (mixtures), baking soda is a single chemical compound and thus not a mixture [2].

Sources

1. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 8: Nature of Matter: Elements, Compounds, and Mixtures > Prepare some questions based on your learnings so far ... ..................................................................................... ..................................................................................... ..................................................................................... ..................................................................................... ..................................................................................... > p. 132