Flux and solder paste

A solder paste comprising:

• a flux and a solder powder,
• wherein the flux comprises an organic acid, an acrylic resin, a rosin, a thixotropic agent, and a solvent, and wherein the flux does not contain water,
• the organic acid includes 1,2,3-propanetricarboxylic acid, and
• a content of the 1,2,3-propanetricarboxylic acid is 0.1% by mass or more and 15% by mass or less with respect to a total amount of the entire flux,
• wherein the solder powder comprises a solder alloy (x) having an alloy composition (x) or a solder alloy (y) having an alloy composition (y),
• wherein the solder alloy (x) having the alloy composition (x) comprises As:
• 25 to 300 mass ppm, Pb:
• more than 0 mass ppm and 5100 mass ppm or less, at least one of Sb:
• more than 0 mass ppm and 3000 mass ppm or less and Bi:
• more than 0 mass ppm and 10000 mass ppm or less, and a balance of Sn and
• satisfying the following formula (1) and formula (2),
• 275≤2As+Sb+Bi+Pb (1)
• 0.01≤(2As+Sb)/(Bi+Pb)≤10.00 (2)
• in the formula (1) and the formula (2), As, Sb, Bi, and Pb each represent the content, in mass ppm, in the alloy composition (x),
• the solder alloy (y) having the alloy composition (y) comprises As:
• 10 mass ppm or more and less than 25 mass ppm, at least one of Bi:
• more than 0 mass ppm and 10000 mass ppm or less and Pb:
• more than 0 mass ppm and 5100 mass ppm or less, Sb:
• more than 0 mass ppm and 3000 mass ppm or less, and a balance of Sn and satisfying the following formula (3) and formula (4),
• 300≤3As+Sb+Bi+Pb (3)
• 0.1≤{(3As+Sb)/(Bi+Pb)}×100≤200 (4)
• in the formula (3) and the formula (4), As, Sb, Bi, and Pb each represent a content, in mass ppm, in the alloy composition (y).