3. This titration served to standardize the NaOH. Since the reaction between KHP and NaOH is of 1:1 stoichiometry To also determine the concentration of NaOH in the KHP solution. 25.49 ml of NaOH were required to neutralize .5208g of KHP (m.w.204.33) dissolved in water. Bala view the full answer Taking the value of 9.50 cm3 and mass of 2 grams, the concentration of NaOH should have been 0.103 mol, but the value I obtained due to the excessive deviation gave me 0.0937 mol. Question at bottom. Moles (nvf) of KHP in volumetric flask = mKHP/MKHP where MKHP is the Molar Mass of KHP (204.22 g), Moles of KHP in 10 cm3 of solution in where V is a given volume of water, Volume of NaOH added = Final Volume – Initial Volume, [c]KHP = (n/V) mol dm-3 = (0.00974/0.1) mol dm-3 = 0.0974 mol dm-3. This way, we avoid excess NaOH from being added. thank you so much!! You should report 4 significant figures, e.g. Science Teacher and Lover of Essays. I just what to know how to solve these … When KHP and NaOH combine, a positive hydrogen ion leaves the KHC8H4O4 and a negative hydrogen atom leaves the NaOH. This preview shows page 17 - 22 out of 30 pages.. KHP solution (L) 0.0125 0.0120 0.0120 Molarity of NaOH to neutralize KHP solution (mol/L) 0.5882 0.6140 0.6133 Molarity of NaOH to neutralize KHP solution (M) 0.5882 0.6140 0.6133 Sample Calculation For The Average Molarity of Sodium Hydroxide, NaOH solution :- 0.0125 0.0120 0.0120 Molarity of NaOH to neutralize KHP For example, in trial 1, I used 11.0 cm3 of NaOH, which is 1.50 cm3 off 9.50 cm3, and in my rough trial, the volume used was 9.9 cm3 and in trial 2, the amount used up was 10.4 cm3. Hypothesis: When KHP is added to the solution of NaOH and the indicator, the solution will turn clear and neutralize. now the base is the NaOH right? 2. The theoretical value of NaOH to be poured was 9.50 cm3, and more or less than 0.1 cm3 of that value. Chemistry Q&A Library Calculate the molarity of a NaOH solution if 24.50 mL of NaOH is titrated with 0.550 grams of KHP and 1.25 mL of 0.100 M HCl is required. However, as NaOH was added further, there came a point when no amount of stirring changed the pink colour. calculate the molarity ofthe NaOH solution: mass of KHP 2.484 g; 75,994 results, page 72 chemistry. Since it was a pure sample of KHP its number of moles is the same as NaOH. Use your average value of NaOH volume to calculate its molarity. In this reaction as well, one mole of KHP completely reacts with one mole of NaOH. The concentration of NaOH is going to be very low because it is diluted. Mass of KHP 0.3148 Initial volume of NaOH 0.4 mL Final volume of NaOH 16.05 ml. Therefore, NaOH solution is standardized by titrating weighed samples of a primary standard acidic substance, potassium hydrogen phthalate (KHC 8 H 4 O 4 , "KHP", molar mass 204.2 g). NaOH has 1 equivalent per mole so Normality = Molarity. sorry, i put the balanced eq in the quote box (i am new to this..kind of confusing) so, here is the balanced eq: KHP + NaOH --> H20 + Na + KP, Yeah that is close enough, you need to make the Na+ and KP- to be correct but it is close enough. Using that solution, the average concentration of potassium hydrogen phthalate was found to be 27.99% in the #52 LO unknown Discussion: In this experiment, the goal was to first find the molarity of NaOH solution by using a buret filled with NaOH solution that was made before the titration began and a flask with distilled water, KHP, and three drops of phenolphthalein solution in it. To obtain the moles of KHP, the mass had to be multiplied by one mole over 204.3grams (3). i wrote the balanced equation but i am not sure what to do next because KHP is given in grams and it doesnt say how much ml of KHP is in the solution. D. Molarity of NaOH from Sample 1 Sample 1 contained 0.002509 mole of KHP, and required 0.02275 L of NaOH to reach the endpoint (indicator color change). 퐾퐻퐶 2 퐻 3 푂 3 (푎푞) + 푁푎푂퐻(푎푞) → 퐻.푂(푙) + 퐾푁푎퐶 2 퐻 3 푂 3 (푎푞) (2) By recording the weight of the sample of KHP and the volume of base needed to neutralize it, the molarity of NaOH can be found. 2. The resultant Acidic solution was transparent, with a small amount of undissolved granules of KHP. What is the molarity of the base? The average molarity of the sodium hydroxide solution was found to be 0.155 M after standardization. 2. College Chemistry Solution for What is the molarity of a NaOH solution if 32.47 mL is required to titrate 0.6013 g of potassium hydrogen phthalate (KHC8H4O4)? Calculate and enter the molarity of your three acetic acid trials using the volume of standardized NaOH solution required for each and the average molarity of the NaOH solution from the standardization trials with KHP. V (L) Moles NaOH M NaOH NaOH = 2. You cannot then use this concentration of NaOH to estimate the percentage composition of the same KHP. The uncertainty of 2.57% indicates that my values were accurate up to within ±2.57%. It only takes seconds! atmosphere). KHP stands for potassium hydrogen phthalate, which has the chemical formula KHC8H4O4. The NaOH may not have reacted with the exact amount of KHP expected. yeah so it would be .009 mol of KHP right? ok so you need to convert the .6319g of KHP to moles of KHP can you do that? The reaction between NaOH and KHP (molar mass 204.23 g/mole) is as follows: NaOH + HOOC-C6H4-COOK Æ NaOOC-C6H4-COOK + H2O By measuring the volume of the ~0.2M NaOH solution dispensed from the buret that is necessary to react completely with a weighed sample of KHP, the exact concentration of NaOH solution is calculated. You can't titrate NaOH by KHP. What mass (in grams) of "KHP" should be used for the standardization of a NaOH Mass Of KHP 0.3148 Initial Volume Of NaOH 0.4 ML Final Volume Of NaOH 16.05 Ml. Part 3: Titration of Vinegar 1. so i am done? Hypothesis: When KHP is added to the solution of NaOH and the indicator, the solution will turn clear and neutralize. that is correct right? Question: in a neutralization reaction 45.7 mL of 0.500 M sulfuric acid is required to completely react with 20.0 mL of sodium hydroxide. A 50.00-mL sample of groundwater is titrated with 0.0900 M EDTA. However, the amount I added on an average was 10.4 cm3, which suggests why the solution became unusually dark pink as supposed to light pink. From the titration data, you will calculate the molarity of the unknown KHP solution to 4 significant figures. Since the reaction between KHP and NaOH is of 1:1 stoichiometry, this means that 0.002509 mole of NaOH must have been used. The percentage uncertainty calculated of the concentration of NaOH was 2.57%, which indicates that the level of precision, although not low, could have been better. However, there has been a deviation of 0.9 cm3, which is significant, but not high. so 2M=N (see page 487 in the textbook) L. 1. NaOH + HOOC-C6H4-COOK Æ NaOOC-C6H4-COOK + H2O By measuring the volume of the ~0.2M NaOH solution dispensed from the buret that is necessary to react completely with a weighed sample of KHP, the exact concentration of NaOH solution is When the solution starts becoming dark pink abruptly, immediately reduce the rate of flow of NaOH from the burette, and after the pink can no longer be eliminated, shut off the supply. Now I need to calculate the average molarity of NaOH titrant based on the color change as indication of equivalence point. MW (KHP) g of KHP Moles KHP = 2. Record all the titration volume in the table and calculate (i) Molarity of prepared NaOH solution, (ii) Molarity of standardized NaOH solution (iii) moles of NaOH in 500mL, (iv) mass of NaOH in 500mL (v) % Purity of NaOH (s) 35 The resulting percentage error out of this deviation is: There is almost a 1% deviation. If 25.21 mL of #NaOH# solution is required to react completely with .550 g #KHP#, what is the molarity of the #NaOH# solution? A 25.00-mL aliquot of an unstandardized HCl solution is titrated with the previously standardized NaOH solution from #1 above. ...Titration Lab of NaOH and KHP Aim: To titrate Sodium Hydroxide with Potassium Hydrogen Phthalate . 0.009 mol KHP x 1 mol NaOH / 1 mol KHP = 0.009 mol NaOH now to get Molarity of NaOH you need, mol NaOH / Liters of NaOH solution so convert your mL to L It is important to note that the pink color in three titrations were all slightly different, some being darker than others. The NaOH solution is a 50% by mass NaOH (.15mole), density of 1.525g/ml The average molarity of the NaOH from the KHP trials i got was 0.1405m Trials (volume) #1: 47.50ml acetic acid 47.50ml NaOH #2: 33.50ml acetic acid The volume of the volumetric flask is 250.0 mL. If the molarity of the NaOH was 0.0625M, this is what must be used in the calculations. The percent error that has resulted is: 9.03% is by far a significant error that has resulted from a small error in the volume. It was crucial to make use of the half drop technique as well because the endpoint was very sensitive to even 0.05 mL. Finally, the molarity of the sodium M = What is the molarity of a NaOH solution if 26.55 ml are needed to titrate a .6939g sample of KHP? HP − + H 2 O ⇌ P 2− + H 3 O + KHP can be used as a buffering agent in combination with hydrochloric acid (HCl) or sodium hydroxide (NaOH) depending on which side of pH 4.0 the buffer is to be. Using flask 1 details, moles NaOH = 0.0247 x 0.0625 = 1.54375 x 10^-3 Moles KHP in sample = 1.54375 x 10^-3 Our first year students titrate a measured mass of a standard, solid, monoprotic acid called Potassium Hydrogen Phthalate (KHP). Dilute this to about 50 mL with water. [c]NaOH = n/V = (0.00979/0.0950) = 0.103 mol dm-3 (cm3 is converted into dm3), Weight of weighing boat before adding KHP = 2.67 g, Weight of weighing boat with KHP = 4.67 g, Weight of weighing boat after transfer = 2.68 g, Mass of KHP Transfer = Weight of weighing boat with KHP – Weight of weighing boat after transfer, *Initial volume is the initial reading of the burette and final volume is the reading after adding NaOH solution, From mole ratio, number of moles of NaOH = 0.00974 mol. Unformatted text preview: Determination of the Molarity of NaOH with KHP *KHP is an abbreviation for potassium hydrogen phthalate (KHC8H4O4) KHC8H4O4 (aq) + NaOH (aq) → KNaC8H4O4 (aq) + H2O (l) Data: Mass of Beaker Mass of KHP & Beaker 3 sf Mass of KHP Initial NaOH buret reading Final NaOH buret reading 4 sf mL of NaOH used Calculations: Trial 1 121.371g Trial 2 120.659g 118.615 121.981g … Free proofreading and copy-editing included. 1. Titration data for four trials for approximately 0.50 g of KHP titrated with NaOH of unknow concentration. Once the This would increase the volume of the NaOH used, changing the molarity. Finally, the molarity of the sodium hydroxide solution can be determined: M = # mol NaOH Volume determined from the buret – … His . To standardize a sodium hydroxide (NaOH) solution against a primary standard acid [Potassium Hydrogen Phthalate (KHP)] using phenolphthalein as indicator. 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