In HNO3, the oxidation number of hydrogen (H) is +1, the oxidation number of nitrogen (N) is +5, and the oxidation number of oxygen (O) is -2. This gives a total oxidation number of 0 for the entire molecule, as HNO3 is a neutral compound. **

To concentrate HNO3, you can use a process called distillation. First, you would need to set up a distillation apparatus, which typically includes a round-bottom flask, a condenser, and a receiving flask. Then, you would heat the HNO3 solution in the round-bottom flask, causing the HNO3 to vaporize. The vapor would then travel through the condenser, where it would condense back into a liquid and collect in the receiving flask, resulting in a more concentrated HNO3 solution. It's important to note that HNO3 is a strong oxidizing agent and can be hazardous, so proper safety precautions should be taken when working with it. **

When NaCl and HNO3 react, the sodium chloride (NaCl) dissociates into its ions, Na+ and Cl-, in the presence of the nitric acid (HNO3). The hydrogen ions (H+) from the nitric acid then react with the chloride ions to form hydrochloric acid (HCl), while the nitrate ions (NO3-) from the nitric acid combine with the sodium ions to form sodium nitrate (NaNO3). Therefore, the overall reaction results in the formation of hydrochloric acid and sodium nitrate. **

To neutralize K2CO3 with HNO3, you would add the nitric acid (HNO3) to the potassium carbonate (K2CO3) solution in a controlled manner while monitoring the pH. The reaction between the two will produce potassium nitrate (KNO3), carbon dioxide (CO2), and water (H2O). The goal is to add just enough HNO3 to completely react with the K2CO3 and bring the solution to a neutral pH of 7. Once the pH is neutral, the reaction is complete and the K2CO3 has been effectively neutralized. **

HNO3 should not look like the image provided because it is a colorless liquid at room temperature. The image shows a brownish, solid substance, which does not accurately represent the physical properties of HNO3. Additionally, HNO3 is a highly corrosive and reactive substance, so it is typically stored in specialized containers to prevent contact with air and moisture, rather than being left exposed in an open dish as shown in the image. **

Yes, HNO3 can also be written in structural formula. The structural formula for nitric acid (HNO3) shows the arrangement of atoms in the molecule, with each atom represented by its chemical symbol and connected by lines to show the bonds between them. In the case of HNO3, the structural formula would show one hydrogen atom (H) bonded to one nitrogen atom (N), which is in turn bonded to three oxygen atoms (O). **

To distill pure nitric acid (HNO3), you would first need to start with a concentrated solution of nitric acid. The solution is then heated in a distillation apparatus, causing the nitric acid to vaporize. The vapor is then cooled and condensed back into a liquid form, resulting in pure nitric acid. The distillation process helps separate the nitric acid from any impurities or contaminants present in the original solution. **

The solubility of metals in HNO3 varies depending on the specific metal and the concentration of the nitric acid. Generally, metals such as copper, silver, and gold are soluble in concentrated nitric acid, while metals like iron, nickel, and chromium are not very soluble. However, the solubility of metals in HNO3 can also be affected by factors such as temperature and the presence of other substances in the solution. **