Oxalic acid has the formula C2H2O4 (HOOC-COOH) so it is diprotic . Therefore, the equivalent weight of crystalline oxalic acid = 63. If you prepare 1.0 N solution of oxalic acid, you need to dissolve 6.30 g of it in enough distilled water to have a solution with total volume of 100 mL. Place the oxalic acid solution in a flask with few drops of an indicator (ph.ph can be used).

Pour the volume you select for 0.1 N solution (it is the same as 0.1 M solution) of NaOH in the buret but since it is still not standardized, the concentration will be considered as unknown.

Add NaOH solution titrant to the analyte until the end point is reached.

Apply the equation N x V (oxalic acid) = N' x V' (NaOH), where N,V, and V' are known. Find out N' which will not be far from 0.1 (probably 0.13 to 0.97 ).

Use the NaOH normality you get for citric acid estimation by titration.

Use the same concentration, 0.1N.

it is better not to work with normality. NaOH 0.1 N is 0.1 M. For NaOH titration you can use 10 mL 0.05 M oxalic acid and phenolphthalein as indicator. Calculate NaOH concentration with the equation 2CacidVacid = CbaseVbase (use molar concentrations)

Use titration method.

Pipette 25ml of 0.1N Naoh in volumetric flask

Put the Oxalic acid in a burette titrate against the base with a suitable indicator. End point give the volumes of acid

Balance the equation b/w the acid and the base ratio 1:2

Calculate the concentration of the acid that ......

Thanks

To standardize a 0.1 N sodium hydroxide (NaOH) solution using oxalic acid, follow these steps in a precise and methodical manner: Preparation of Oxalic Acid Solution: Accurately weigh approximately 1.26 grams of oxalic acid dihydrate (C₂H₂O₄·2H₂O). This quantity is based on the formula weight of oxalic acid dihydrate, which is 126 g/mol. Dissolve this weighed amount in distilled water and dilute it to 250 ml in a volumetric flask. This creates a solution where 1 ml is equivalent to 0.1 meq of NaOH. Titration Setup: Rinse a burette with the NaOH solution and then fill it. Pipette a known volume (say 10 ml) of the oxalic acid solution into an Erlenmeyer flask. Add a few drops of a suitable indicator, such as phenolphthalein, to the oxalic acid solution. Conducting the Titration: Slowly add the NaOH solution from the burette to the oxalic acid solution while continuously swirling the flask. Observe the color change of the solution. The endpoint is reached when the solution turns slightly pink and the color persists for about 30 seconds. Calculation: Record the volume of NaOH used to reach the endpoint. Calculate the normality of the NaOH solution using the formula: Normality of NaOH = Normality of Oxalic Acid × Volume of Oxalic Acid Volume of NaOH used Normality of NaOH= Volume of NaOH used Normality of Oxalic Acid×Volume of Oxalic Acid ​ Since the normality of the oxalic acid solution is known (based on its preparation), and the volumes of both solutions at the endpoint are measured, the normality of the NaOH can be accurately calculated. Repetition for Accuracy: Repeat the titration at least two more times to ensure accuracy and precision. Average the results from the consistent titrations to get the final standardized value of the NaOH solution. 1. **DH5α Characteristics**: - DH5α is a widely used E. coli strain for routine cloning due to its high transformation efficiency. - It is suitable for most cloning purposes, especially for plasmids that do not contain long repeated sequences or other destabilizing elements. - This strain lacks endonuclease I (endA1) activity, which improves the quality of plasmid DNA. It also has a mutation in the recA gene, providing reduced recombination. 2. **Stbl3 Characteristics**: - Stbl3 is specifically designed for cloning of unstable DNA sequences, such as lentiviral vectors that often contain long terminal repeats (LTRs). - It reduces the recombination of LTR sequences due to its recA13 mutation, which provides an even greater reduction in homologous recombination compared to DH5α. - Stbl3 also contains a mcrB mutation, allowing it to clone methylated DNA, which might be relevant depending on your vector. 3. **Considerations for Lentiviral Plasmid Cloning**: - If your lentiviral plasmid is stable and doesn't have sequences prone to recombination or deletion, DH5α can be a suitable choice. - For plasmids with sequences that could be unstable or prone to recombination (like LTRs), Stbl3 is often preferred as it offers better stability for these elements. 4. **Experimental Validation**: - While theoretically, DH5α could be used, it is advisable to experimentally validate the stability of your plasmid in this strain. - Compare the transformation efficiency, plasmid yield, and sequence integrity between the two strains for your specific plasmid. In conclusion, while DH5α can be used for lentiviral plasmid cloning, careful consideration of the plasmid’s stability and the characteristics of both E. coli strains is necessary to ensure successful cloning. If there's any uncertainty about the stability of your plasmid in DH5α, Stbl3 is a safer choice due to its enhanced ability to maintain unstable sequences.

l Reviewing the protocols listed here may offer further guidance in addressing this issue.