# Standardizing a Sodium Hydroxide Solution

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PURPOSE The purpose of this experiment is to use our knowledge from previous experiments to determine the exact concentration of a 0.1M sodium hydroxide solution by titration (Lab Guide pg.141). QUESTION The question that was proposed for investigation was: Can the exact concentration of 0.1M sodium hydroxide solution be determined by titration (Lab Guide pg. 141)? BACKGROUND DISCUSSION For this experiment we used titration to standardize the exact concentration of NaOH. Titration is the process of carefully adding one solution from a buret to another substance in a flask until all of the substance in the flask has reacted. Standardizing is the process of determining a solutions concentration. When a solution has been standardized it is referred to as a standard solution. To know when a solution is at its end point an indicator is added to acidic solution. An indicator is an organic dye that is added to an acidic solution. The indicator is one color is in the acidic solution and another color in the basic solutions. An end point occurs when the organic dye changes colors to indicate that the reaction is over (Lab Guide pg. 141). Sample Calculations In this experiment three different equations were used and they are the Stoichiometry of Titration Reaction, Converting mL to L, and Calculating the Molarity of NaOH and HCl (Lab Guide pg. 142 and 143). Stoichiometry of Titration Reaction: H_3 O^+ (aq)+〖OH〗^- (aq)→2H_2 O (l) Converting mL to L: (_^V)NaOH=(24.42mL)(1L/1000mL)= 〖2.442×10〗^(-2) L (_^V)HCl=(25.00mL)(1L/1000mL)= 〖2.500×10〗^(-2) L Calculating the Molarity of NaOH and HCl: (_^M)NaOH=(((_^M)HCL)((_^V)HCl,L))/(((_^V)NaOH,L) ) PROCEDURE (Attached) STUDENT REPORT DATA SHEET (Attached) ANALYSIS OF DATA HYPOTHESIS: I hypothesize that by titrating a known amount of a substance in a solution, I can use the data from the experiment to calculate how many moles of the solution of the known concentration were required to completely react with the titrant and then using the formula C=n/V(in liters) to calculate the molarity of NaOH. OBSERVATIONS: In this experiment the Sodium Hydroxide solution went through three different phases where its quality and quantity changed. The first phase was called I. Preparing Approximately 0.1M NaOH, 1000mL of clear distilled water was boiled and then chilled to room temp.