Article in English: Find the concentration of the acid solution on the label, or in the word problem you are working on. This number is often written in units of molarity, or molar concentration, abbreviated as M. For example, a "6M" acid contains six moles of acid molecules per liter. We'll call this starting concentration C1. The formula below will also use the term V1. This is the volume of the acid we will be adding to water. We probably won't use the entire bottle of acid, though, so we don't know what this number is yet. The desired concentration and volume of acid is typically determined by a school assignment or by the requirements of the laboratory you are working in. For example, we might want to dilute our acid to a concentration of 2M, and need 0.5 liters (0.1 US gal). We'll call this desired concentration C2 and the desired volume V2.  If you are using unusual units, convert them all to units of molar concentration (moles per liter) and liters before you continue. If you are not certain what concentration or volume of acid is required, consult your teacher, a chemist, or an expert in the task you plan to use acid in. Whenever you prepare to dilute a solution, you can use the formula C1V1 = C2V2. words, this means "the initial solution's concentration x its volume = the diluted solutions' concentration x its volume." We know this is true because concentration x volume = the total amount of acid, and the total amount of acid will remain the same as it is added to the water. In our example, we can write this formula (6M)(V1)=(2M)(0.5L). This term, V1, will tell us how much of the initial acid solution we need to add to water in order to end up with the desired concentration and volume. Rearrange the formula as V1=(C2V2)/(C1), then plug in the numbers you know. In our example, we would end up with V1=((2M)(0.5L))/(6M)=1⁄6 liter (0.0 US gal). This approximately equals 0.167 liters (0.0 US gal), or 167 milliliters. Now that you now V1, the amount of acid you'll be using, and V2, the amount of solution you'll end up with,...

Summary in Indonesian:
Periksa hal-hal yang sudah Anda miliki. Tentukan hasil akhirnya. Tulislah rumus untuk menghitung pengenceran. Selesaikan rumus untuk V1. Hitunglah banyaknya air yang Anda butuhkan.