Answer: an increase in the concentration of
in aqueous solutions and is capable of donating one or more 
Explanation:
According to Arrhenius concept, a base is defined as a substance which donates hydroxide ions
when dissolved in water and an acid is defined as a substance which donates hydrogen ions
in water.
According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
Thus According to the Arrhenius concept, an acid is a substance that causes an increase in the concentration of
in aqueous solutions and is capable of donating one or more 
I think u turn down the heat not to sure
Answer:
gold wire (Au)
Explanation:
A substance that cannot be separated or broken down into simpler substances by chemical means is an element.
Between the given options only gold wire is an element, Au.
A way of knowing that it is an element is noticing that its formula is a single symbol which corresponds to an element found in the periodic table, unlike a combination of said symbols (like NaCl or H₂O).
Answer:
It is known generally that polar compounds are soluble in polar solvents. Based on the structure of benzoic acid, it comprises the non-polar C6H6 group and polar COOH group. Based on the structure, in benzoic acid, the nonpolar hydrocarbon outweighs and influences the polar part as nonpolar, due to which benzoic acid is not soluble in water.
On the other hand, benzoic acid produces sodium salt benzoic acid when it reacts with 2.5 M sodium hydroxide, this salt is ionic. Generally, the ionic compounds are soluble in water. Therefore, the salt of benzoic acid gets dissolved in water. Hence, benzoic acid is soluble in the solution of sodium hydroxide.