17. Record results to determine if lactic acid decreases or increases the pH of the water. 18. If the lactic acid increases the pH of the water, it shows that lactic acid increases the pH of the blood and if lactic acid decreases the pH of the water, it shows that lactic acid will decrease the pH of the blood. 19.
In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.
Chloroacetic acid (0.5 g, 5. 28 mmol), 5-aminotetrazole monohydrate (0.45 g, 5. 28 mmol), and sodium hydroxide (0.59 g, 10.57 mmol) in 10 ml of water was refluxed 20 hr, cooled, and made strongly acidic with concentrated hydrochloric acid. The mixture was cooled overnight and precipitate was separated to give 0.28 g a white solid product at 45.41% yield. (5-Amino-tetrazol-1-yl)-acetic acid: Yield: 45.41%; white crystals; m.p 210-213°C; IR (KBr): 3388, 3315, 3270, 3205, 3010, 2976, 1697, 1638, 1586, 1496, 1257 cm-1; 13C NMR (75 MHz (DMSO-d6)): 168, 156,
Eventually using the NaOH and the acid’s consumed moles, the equivalent mass will be determined. Procedure: Part 2: Obtain 45mL of NaOH, and then weigh 0.3-0.4g of the unknown acid (KH2PO4). Dissolve the acid into 20.00mL water.
In this experiment, racemic 2-methylcyclohexanone was reduced using sodium borohydride as a nucleophile to give a diastereomeric mixture of cis and trans secondary alcohols. The products were analyzed for purity using IR spectroscopy and gas chromatography. 1.2 g of 2-methylcyclohexanone and 10 mL of methanol were combined in a flask and cooled in an ice bath. Two 100 mg portions of sodium borohydride were added to the flask and stirred. 5 mL of 3M sodium hydroxide, 5 mL of de-ionized water, and 15 mL of hexane were added to the reaction flask and stirred.
Then, the UV absorbance of the five standards was taken. Water was used in the reference cuvet. The wavelength of the peak absorbance for caffeine was also taken. The spectroscopy machine automatically corrected the absorbance values against the baseline of the water reference.
Catalytic reduction of p-nitrophenol As a model reaction, we selected the reduction of 4-NP by NaBH4 to 4-AP. The reduction was followed with the aqueous solution in a standard quartz cell with a 1cm path length. The reaction process was as follows: 1.5 mL of 0.15 mM 4-NP was mixed with 1.0 mL of 0.02 M NaBH4 in the cell for UV-Vis measurements. Immediately, the colour change was observed from light yellow to deep yellow. 0.5 mL of AuNPs solution was added to the above mixture. The UV-Vis spectra were recorded with a time interval of 1 min in a scanning range of 200-600nm at ambient temperature (25±20C).
After the evaluation of stomach for ulcers, the gastric mucosa of glandular portion was scrapped with the help of two glass slides, weighed (100 mg) and homogenized in 1 mL of a 0.15 M, ice cold potassium chloride (KCl) solution and centrifuged at 3,000 RPM for 10 minutes (REMI centrifuge). 1 mL of suspension was taken from the above tissue homogenate in test tube and 0.5 mL of 30% w/v TCA (trichloroacetic acid) was added to it, followed by 0.5 mL of 0.8% w/v TBA (thiobarbituric acid) reagent. The tubes were then covered with aluminium foil and kept in water bath for 30 minutes at 80 °C. After 30 minutes, tubes were taken out and kept in ice-cold water for 30 minutes and centrifuged at 3000 rpm for 15 minutes (R-BC DX REMI centrifuge). The absorbance of the supernatant was read in spectrophotometer (UV-1601, SHIMADZU) at 540 nm against blank.
The ion exchange capacity is measured by the chemical titration [Hasimi A, Stavropoulou A, Papadokostaki KG, Sanopoulou M. Euro Polym J (2008) 4098-107]. In order to measure the IEC values, the dry samples were soaked in 1M aqueous NaCl solution at room temperature for 24 hours to exchange of proton by sodium ions. The ion-exchanged NaCl solution was back titrated with 0.1M NaOH solution using phenolphthalein as an indicator. The protonic conductivity measurements were made through via Nyquist plot using N4L PSM 1735 series LCZ meter with amplitude of 10 mV from 1 Hz to 1 MHz The proton conductivity values are calculated
Five ml of reaction mixture 248 containing 50 mm phosphate buffer (pH 7.8), 13 mm methionine, 75 mm NBT, 2 mm 249 riboflavin, 0.1 mm EDTA and the enzyme extract. Absorbance of sample was read at 560 250 nm. The difference of percentage reduction of colour development in blank and the 251 sample was calculated. Fifty percent reduction in the colour was taken as one unit of 252 enzyme activity and was expressed in enzyme units per milligram protein (U mg-1 253 protein). 254 2.11.3.
The dried roots of Inula racemosa were pulverized and sieved with 100 ~ 200 mesh. The herb powder was placed into a glass bottle. Ultrasound-assisted extraction was carried out in an ultrasonic cleaner RK102H (Bandelin sonorex, Germany). The powder of Inula racemosa was extracted three times under the following conditions: the ratio of material to solvent was 10:1, undergoing ultrasonic treatment 30 minutes at 25 °C, 100 kHz /450 W.31 Before large extraction, a small-scale extraction experiments were carried out: 95% ethanol and ethyl acetate as the extractive solutions was investigated, respectively.